Molecular re-engineering of excitation-inhibition balance in memory circuits

ABSTRACT

Memory-regulating agents and methods that target actin binding LIM protein family, member 3 (ABLIM3).

CLAIM OF PRIORITY

This application is a divisional of U.S. patent application Ser. No.15/125,796, filed Sep. 13, 2016, which is the National Stage under 371of International Application No. PCT/US2015/020540, filed on Mar. 13,2015, which claims the benefit of U.S. Provisional Application Ser. No.61/952,934, filed on Mar. 14, 2014. The entire contents of the foregoingare incorporated herein by reference.

TECHNICAL FIELD

Described are memory-regulating agents and methods that target actinbinding LIM protein family, member 3 (ABLIM3).

BACKGROUND

Central to efforts to developing novel therapeutics for reversingcognitive and mood impairments associated with Alzheimer's Disease (AD),psychiatric illnesses such as PTSD and during normal aging, isidentifying the underlying dysfunctional neural circuits and restoringtheir functional properties.

SUMMARY

As described herein, Ablim3 has been identified as a molecular brake ofDG axonal filopodia and functions in enhancing memory strength andprecision and pattern separation. Thus described herein are methods ofinhibiting Ablim3 using inhibitory nucleic acids that target the Ablim3gene or mRNA; and a cell-based assay that can be used to screen forsmall molecule regulators of Ablim3 function, to improve memory insubjects, e.g., subjects with memory dysfunction associated with AD,normal aging, or PTSD.

Thus, provided herein are methods for improving memory in a subject; themethods comprise administering to the subject an effective amount of aninhibitory nucleic acid targeting actin binding LIM protein family,member 3 (ABLIM3).

In some embodiments, the subject has memory dysfunction associated withnormal aging or Alzheimer's Disease. In some embodiments, the subjecthas post-traumatic stress disorder.

In some embodiments, pattern (memory) separation is improved in thesubject.

In some embodiments, the inhibitory nucleic acid is 5 to 40 bases inlength (optionally 12-30, 12-28, or 12-25 bases in length). In someembodiments, the inhibitory nucleic acid is 10 to 50 bases in length. Insome embodiments, the inhibitory nucleic acid comprises a base sequenceat least 90% complementary to at least 10 bases of the Ablim3 RNAsequence. In some embodiments, the inhibitory nucleic acid comprises asequence of bases at least 80% or 90% complementary to, e.g., at least5-30, 10-30, 15-30, 20-30, 25-30 or 5-40, 10-40, 15-40, 20-40, 25-40, or30-40 bases of the RNA sequence. In some embodiments, the inhibitorynucleic acid comprises a sequence of bases with up to 3 mismatches(e.g., up to 1, or up to 2 mismatches) in complementary base pairingover 10, 15, 20, 25 or 30 bases of the RNA sequence. In someembodiments, the inhibitory nucleic acid comprises a sequence of basesat least 80% complementary to at least 10 bases of the RNA sequence. Insome embodiments, the inhibitory nucleic acid comprises a sequence ofbases with up to 3 mismatches over 15 bases of the RNA sequence. In someembodiments, the inhibitory nucleic acid is single stranded. In someembodiments, the inhibitory nucleic acid is double stranded.

In some embodiments, the inhibitory nucleic acid comprises one or moremodifications comprising: a modified sugar moiety, a modifiedinternucleoside linkage, a modified nucleotide and/or combinationsthereof. In some embodiments, the inhibitory nucleic acid is anantisense oligonucleotide, LNA molecule, PNA molecule, ribozyme orsiRNA. In some embodiments, the inhibitory nucleic acid is doublestranded and comprises an overhang (optionally 2-6 bases in length) atone or both termini. In some embodiments, the modified internucleosidelinkage comprises at least one of: alkylphosphonate, phosphorothioate,phosphorodithioate, alkylphosphonothioate, phosphoramidate, carbamate,carbonate, phosphate triester, acetamidate, carboxymethyl ester, orcombinations thereof. In some embodiments, the modified sugar moietycomprises a 2′-O-methoxyethyl modified sugar moiety, a 2′-methoxymodified sugar moiety, a 2′-O-alkyl modified sugar moiety, or a bicyclicsugar moiety. In some embodiments, the inhibitory nucleic acid comprisesone or more of 2′-OMe, 2′-F, LNA, PNA, FANA, ENA or morpholinomodifications.

In some embodiments, the inhibitory nucleic acid is selected from thegroup consisting of antisense oligonucleotides, ribozymes, externalguide sequence (EGS) oligonucleotides, siRNA compounds, micro RNAs(miRNAs); small, temporal RNAs (stRNA), and single- or double-strandedRNA interference (RNAi) compounds.

In some embodiments, the RNAi compound is selected from the groupconsisting of short interfering RNA (siRNA); or a short, hairpin RNA(shRNA); small RNA-induced gene activation (RNAa); and small activatingRNAs (saRNAs).

In some embodiments, the antisense oligonucleotide is selected from thegroup consisting of antisense RNAs, antisense DNAs, and chimericantisense oligonucleotides.

Also provided herein are methods for identifying a candidate smallmolecule inhibitor of Ablim3. The methods include providing a testsample comprising a population of cells that express Ablim3; contactingthe sample with a test compound; detecting subcellular localization ofAblim3 protein in the cells in the presence of the test compound;determining whether the Ablim3 protein is localized to adherensjunctions in the cells in the presence of the cells; selecting as acandidate inhibitor a test compound that reduces localization of Ablim3protein to adherens junctions.

In some embodiments, the cells express an Ablim3 reporter construct,wherein Ablim3 is linked to a detectable label, preferably a fluorescentprotein.

In some embodiments, the methods include evaluating actin cytoskeletonin the cells, and selecting as a candidate inhibitor a test compoundthat reduces localization of Ablim3 protein to adherens junctions anddoes not disrupt the actin cytoskeleton

In some embodiments, the methods include administering a candidatecompound to an animal model; evaluating an effect of the candidatecompound on memory in the animal model; and selecting a compound thatimproves memory in the animal model.

In some embodiments, the compound improves pattern separation in theanimal model.

In some embodiments, the test compound is a polypeptide, polynucleotide,inorganic large or small molecule, or organic large or small molecule.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Methods and materials aredescribed herein for use in the present invention; other, suitablemethods and materials known in the art can also be used. The materials,methods, and examples are illustrative only and not intended to belimiting. All publications, patent applications, patents, sequences,database entries, and other references mentioned herein are incorporatedby reference in their entirety. In case of conflict, the presentspecification, including definitions, will control.

Other features and advantages of the invention will be apparent from thefollowing detailed description and figures, and from the claims.

DESCRIPTION OF DRAWINGS

FIGS. 1A-C. Increased FFE-FFI ratio and decreased adult hippocampalneurogenesis in aging. A-B. Wiring diagram and anatomical labelingshowing segregation of FFI and FFE in MFTs and MFT-filopodia (redasterisks) in DG-CA3 circuit in adulthood and aging. Line thicknessconveys strength. Activation of CA3 neurons in contexts A and B conveysglobal remapping. C. Reduced MFT-filopodia, increased MFT size, anddecreased adult hippocampal neurogenesis in aged mice (C). n>50 MFTs (B)and n=3-4 mice/gp (B-C). Data are mean+/−S.E.M. *p<0.05.

FIGS. 2A-F. Aged mice show impaired contextual discrimination precision,increased CA3 activation during retrieval, and dampened learning-inducedenhancement of FFI connectivity. A. Experimental design for behavioraltesting and analysis of circuit activation and FFI connectivity. B-C.Assessment of encoding and memory precision in adult, middle aged andaged mice using a contextual fear discrimination learning paradigm. D.c-fos immunohistochemistry following exposure to context B. Aged miceshow increased number of low c-fos+ve cells (arrowheads) and fewer highc-fos+ cells (arrows) in CA3 compared to adult mice. DG activation islower in aged mice. E-F. Aged mice fail to show potentiation ofMFT-filopodial contacts with SL PV+ interneurons following learning(after context B). n=10-12 mice/gp (B-C), n=4-6 mice/gp, subset of miceused in B-C (D), n=4-6 mice/gp (E-F), n>50 MFTs. Data are mean+/−S.E.M.*p<0.05.

FIGS. 3A-E. Ablim3 colocalizes to PAJs within MFTs and a model showinghow Ablim3 levels dictate MFT stabilization, MFT remodeling andMFT-filopodial number. A. ISH and immunohistochemistry for Ablim3 inadult hippocampus and whole brain sections. B-C. Ablim3 localizes toPAJs (ZO1+), but not active zones (Bassoon+), within MFTs (VGLUT1+). D.Ablim3 expression is increased in aged mice following CFD. E. Model forhow Ablim3 levels dictate MFT remodeling and MFT-filopodial number.n=4-6 mice/gp (D). Data are mean+/−S.E.M. *p<0.05.

FIGS. 4A-B. Analysis of FFE and FFI connectivity during adult-born dgneuronal maturation and molecular control of FFE connectivity inadult-born dg neurons. A. 4 weeks old adult-born neurons show highestMFT-filopodia number and MFT size increases with maturation. Inset:Retroviral labeled adult-born dg neurons of different ages, MFTs and lowmagnification of DG-CA3. B. Ablim3 overexpression in 4 weeks oldadult-born neurons increases MFT size. At least n=50 MFTs and n=3 miceper timepoint (A-B). Data are mean+/−S.E.M. *p<0.05.

FIGS. 5A-F Ablim3 down regulation in dg neurons in adult and aged miceincreases FFI connectivity. A. Characterization of shRNAs targetingAblim3. Western blot and Ablim3 immunohistochemistry showing completeknockdown of Ablim3 in 293T cells in vitro and in vivo with shRNAs 46and 47. B. Schematic of lentiviral construct used for Ablim3 knockdownin vivo. Representative images of MFTs from adult (3mos) mice injectedwith NTshRNA or shRNA46. shRNA46 expressing MFTs have multiple VGLUT1+filopodia that contact PV interneurons in CA3ab. Quantification of MFTsize, MFT filopodia number and length. C. Quantification of dg neuronaldendritic spine density following lentiviral mediated Ablim3 knockdown.D-E. shRNA 46 increases MFT-filopodia number in mature dg neurons ofaged (16 mos) mice without changing dendritic spine density and sizedistribution. F. Retroviral downregulation of Ablim3 in just adult-borndg neurons produces long-lasting enhancement in FFI connectivity (MFTfilopodia). At least n=50 MFTs and n=3 mice per construct. *p<0.05, Dataare mean+/−S.E.M.

FIGS. 6A-B show (A) GFP-Ablim3 constructs used to generate stable celllines (−ve and +ve controls). B, a flowchart for primary and secondaryscreens. White arrows indicate MFT filopodia in Thy-1 GFP, M line.

FIGS. 7A-B. MFT Filopodia number and MFT size during dg neuronalmaturation and following a context discrimination-pattern separationtask. 7A. 4 wk adult-born neurons show highest MFT filopodia number butMFT size increases with maturation. Inset: Retroviral labeled adult-borndg neurons and MFTs. 7B. MFT Filopodia number increases followingdiscrimination between shock context A and similar context B (Freezingin A>B). At least n=50 MFTs (B-C) and n=3 mice per timepoint (B). n=12mice (C). Data are mean+/−S.E.M. *p<0.05.

FIGS. 8A-C. A. Representative images of viral injections of shRNA (NTand #46) into DG of 16 months old aged mice. Experimental design andquantification of long-term contextual fear memory. B. Ablim3downregulation enhances activation of stratum lucidum-PV interneuronsand PV expression levels. C. CA3ab of shRNA #46 mice shows increasedc-fos (High) whereas DG activation is unchanged. N=10-12 mice/group.*p<0.05, ** p<0.01. PV intensity significance (Repeat Measures ANOVA).Data are mean+/−S.E.M.

DETAILED DESCRIPTION

The dentate gyms (DG)-CA3 circuit is the one of the only regions in theadult mammalian brain that is host to neurogenesis, a process by whichstem cells generate new neurons. The DG-CA3 circuit plays a criticalrole in assessing if our day-to-day experiences are different from thosepreviously encountered, a process known as pattern separation. Patternseparation is essential to formation of new memories of places andevents and is impaired during early stages of AD, normal aging andpotentially, in post-traumatic stress disorder (PTSD). As shown herein,adult hippocampal neurogenesis is indispensable for pattern separationsuggesting that it may be harnessed to reverse pattern separationimpairments in the pathological brain. The wiring diagram of the DG-CA3circuit suggests a role for specialized structures called axonalfilopodia on synaptic terminals of DG neurons that modulate levels ofinhibition in the circuit and influence pattern separation. However, thecapacity to generate new axonal filopodia becomes progressivelyrestricted with neuronal maturation and only during learning, is axonalfilopodia-dependent structural plasticity dramatically increased.Without wishing to be bound by theory, it is hypothesized that molecularbrakes that facilitate synaptic stabilization are regulated todestabilize synapses and enhance axonal filopodial plasticity, memorystrength and precision and and pattern separation. Targeting thesemolecular brakes is expected to enhance memory strength and precisionand pattern separation by rejuvenating structural plasticity of axonalfilopodia of adult-born neurons and older neurons in the DG-CA3 circuit.Here, Ablim3 is identified as a molecular brake of DG axonal filopodiaand functions in enhancing memory strength and precision and patternseparation. Thus described herein are methods of inhibiting Ablim3 usinginhibitory nucleic acids that target the Ablim3 gene or mRNA; and acell-based assay that can be used to screen for small moleculeregulators of Ablim3 function.

Targeting FFE-FFI Balance to Enhance Memory in Normal Aging and AD

Aging affects multiple memory systems in the brain and a constellationof cognitive processes normally subserved by these brain regions (Hofand Morrison, 2004). These include impaired ability to form new episodicmemories, spatial navigation, and contextual source memory (Small etal., 2011). The development of effective procognitive interventions foraging necessitates understanding how specific neural circuits within themedial temporal lobe contribute to each of these different memoryfunctions. Episodic memory formation requires a balance of two distinctmnemonic processes, pattern separation and pattern completion in theDG-CA3 circuit of the hippocampus. Whereas, pattern separation in DG isessential to distinguish between similar experiences by minimizinginterference (Treves and Rolls, 1992; O'Reilly and McClelland, 1994;McClelland and Goddard, 1996; Rolls, 1996; Gilbert et al., 2001; Leutgebet al., 2007; McHugh et al., 2007; Bakker et al., 2008), patterncompletion in CA3 facilitates the retrieval of memories based on partialcues (Marr, 1971; McNaughton and Morris, 1987; Nakazawa et al., 2002).Rodent studies suggest that pattern separation-completion balance isdisrupted in aging. At a cellular level this manifests as inflexibleencoding of similar environments by independent neuronal ensembles orimpaired global remapping and elevated CA3 place cell firing (Wilson etal., 2005). At a behavioral level, contextual discrimination and spatialpattern separation is impaired (Creer et al., 2010) (FIG. 2).Interestingly, aged humans and individuals with mild cognitiveimpairment (MCI) show increased activation of CA3 circuitry duringretrieval (Bakker et al., 2012) and impaired discrimination ofperceptually similar objects (Toner et al., 2009; Yassa et al., 2011b;Yassa et al., 2011a; Bakker et al., 2012; Stark et al., 2013). Despitethis evidence for altered DG-CA3 circuit function in aging, the preciseunderlying neurobiological mechanisms are poorly understood. Agingrelated changes in the medial temporal lobe system (MTL) includereduction in perforant path (PP) inputs (Geinisman et al., 1992; Smithet al., 2000; Hof and Morrison, 2004; Yassa et al., 2010), hippocampalneurogenesis (Kuhn et al., 1996; Villeda et al., 2011) (FIG. 1),expression of glutamate decarboxylase-67 in interneurons (Stanley andShetty, 2004) and alterations in the cholinergic system (Decker, 1987;Smith et al., 1993). Although reduced PP-DG connectivity and alteredcholinergic inputs to CA3 has been proposed to result in lowerinhibition onto CA3 pyramidal neurons and consequently, hyperactivationand excessive pattern completion through their highly recurrentcollaterals during retrieval (Hasselmo et al., 1995; Wilson et al.,2005), causal evidence linking changes in excitation-inhibition (E-I)balance and age-related changes in CA3 properties and patternseparation-completion imbalance is conspicuously absent.

As demonstrated herein, a reduction in feed-forward inhibition (FFI) andincrease in feed forward excitation (FFE) in DG-CA3 circuitry causallyrelates to excessive CA3 activation during retrieval and patternseparation-completion imbalance in the aged brain. Importantly, a novelmolecular mechanism has been identified by which connectivity underlyingFFI and FFE in DG-CA3 circuitry can be selectively modulated to causallyassess how changes in FFE and FFI link with CA3 properties and encodingand memory precision. Since changes in FFI in DG-CA3 are downstream toreduction in PP-DG inputs in aging, restoring FFI in DG-CA3 may offsetdecreased PP-dependent activation of DG to reverse patternseparation-completion imbalance and CA3 hyperactivation duringretrieval.

Although altered E-I balance in the MTL (EC-DG-CA3 circuits) has beenproposed to contribute to altered CA3 properties in aging (Wilson etal., 2005), causal evidence is absent owing to a lack of tools thatselectively target E-I balance in this circuit without affecting otherneuronal and circuit properties. We have identified age related changesin connectivity underlying FFE and FFI in the DG-CA3 circuit andincreased CA3 activation in aging that accompanies loss of contextualencoding and memory precision (FIG. 1, 2). FFI has been suggested tofacilitate sparse coding and modulate excitation of the recurrentcollateral circuitry of CA3, features long recognized as conducive topattern separation-completion balance (Treves and Rolls, 1992) (O'Reillyand McClelland, 1994; Bragin et al., 1995) (McClelland and Goddard,1996) (Acsady and Kali, 2007; Torborg et al., 2010; Ikrar et al., 2013;Piatti et al., 2013) (McBain, 2008). Furthermore, FFI connectivity hasbeen implicated in encoding and memory precision (Ruediger et al., 2011;Ruediger et al., 2012). Motivated by these observations, a screen wasperformed to identify selective molecular regulators of FFE and FFIconnectivity in the DG-CA3 circuit. The screen took advantage of thefact that the DG-CA3 circuit shows exquisite anatomical segregation ofFFE and FFI within the MFT (Acsady et al., 1998; McBain, 2008).Specifically, dg neurons make excitatory connections with CA3 neuronsvia large MFTs and onto parvalbumin (PV) +ve inhibitory interneurons instratum lucidum (SL) via vesicular glutamate transporter-1 (VGLUT1) +vefilopodia emanating from the MFTs (referred to as MFT-filopodia) (FIG.1A). Since these interneurons inhibit CA3 neurons, the synapticconnections of MFT-filopodia and MFTs influence E-I balance andactivation of the CA3 recurrent collateral circuitry underlying patterncompletion. Moreover, learning increases MFT-filopodia number andMFT-filopodia number correlates tightly with encoding and memoryprecision (Ruediger et al., 2011; Ruediger et al., 2012). Therefore, wewanted to identify factors that regulate MFT-filopodia and MFT size,respectively without affecting dendritic spine density or inputspecificity. We identified Ablim3 as one such factor which isexclusively localized to mossy fiber terminals (MFTs) and is absent fromhilar mossy cells, interneurons, and hippocampal molecular layers.Importantly, Ablim3 acts as brake on structural plasticity of MFTs (FIG.3, 4). Using newly developed retroviral and lentiviral expressionsystems to downregulate or overexpress Ablim3 in dentate granule (dg)neurons, we found that we can increase the number of MFT-filopodialcontacts with PV+ interneurons or MFT size, respectively, withoutchanging dendritic spine density (FIG. 4, 5). Since Ablim3 functionsthrough its localization at MFT-CA3 spine contact sites known as punctaadherens junctions (PAJs) within MFTs and because MFTs in the hilus lackPAJs (Acsady et al., 1998), viral regulation of Ablim3 expression levelsin dg neurons should selectively impact FFI and FFE without changingfeed-back inhibition onto DG. Thus, we have identified one of the firstmolecular regulators of FFI-FFE balance in the DG-CA3 circuit thatdiametrically dictates MFT size and MFT-filopodial contacts withinterneurons without affecting input specificity of dg neurons.

Targeting FFE-FFI Balance to Enhance Ambiguous Threat Processing

The generation of adaptive fear responses to ambiguous threats in theenvironment is critically dependent on how contexts and cue-contingencyrelationships are encoded. Inefficient encoding of ambiguous threats mayresult in heightened avoidance behavior, overgeneralization of fear,hyper vigilance and arousal, symptoms that characterize anxietydisorders such as PTSD, GAD and panic disorder (Peri et al., 2000;Yehuda and LeDoux, 2007; Grillon et al., 2009; Lissek et al., 2010).Current theories assert that overgeneralization of fear has its originsin time dependent changes in associative learning and decrease infidelity of the memory (Biedenkapp and Rudy, 2007; Wiltgen and Silva,2007; Wang et al., 2009; Sauerhofer et al., 2012) or a failure toincorporate details in CA1 during encoding (Xu and Sudhof, 2013). Thepresent inventors propose that efficient discrimination of ambiguousthreats arises from minimizing interference between overlappingcontextual information or predictors of contingency. One mechanism thatfulfills these functions is pattern separation through global remapping,a mnemonic process by which the DG-CA3 circuit disambiguatesperceptually similar inputs to constrain the retrieval of previouslyencoded memories based on partial cues, a process also referred to aspattern completion (Mari, 1971; O'Reilly and McClelland, 1994; Gilbertet al., 2001; Rolls and Kesner, 2006; Leutgeb et al., 2007; McHugh etal., 2007; Bakker et al., 2008; Yassa and Stark, 2011; Motley andKirwan, 2012). Although work by others and us has implicated adult-borndg neurons in pattern separation (Clelland et al., 2009; Tronel et al.,2010; Sahay et al., 2011b; Nakashiba et al., 2012; Niibori et al.,2012), the circuit mechanisms and neural pathways by which adult-bornneurons process ambiguous threats is not known. By identifyingproperties of adult-born dg neurons instrumental to encoding, we may beable to target these properties in not just adult-born dg neurons, butalso rejuvenate mature dg neurons and reengineer DG-CA3 circuitry tomodulate pattern separation.

Methods of Treatment

Thus, described herein are methods of treating memory dysfunction insubjects in need thereof, e.g., in subjects with memory dysfunctionrelating to normal or abnormal aging (e.g., AD), or in subjects withanxiety disorders such as PTSD, GAD and panic disorder. Generally, themethods include administering a therapeutically effective amount of aninhibitor of Ablim3 as described herein, to a subject who is in need of,or who has been determined to be in need of, such treatment.

As used in this context, to “treat” means to ameliorate at least onesymptom of the disorder associated with memory dysfunction. For example,a treatment can result in a reduction in memory lapses and a return orapproach to normal memory. Administration of a therapeutically effectiveamount of a compound described herein for the treatment of anxietydisorders will result in decreased anxiety.

In some embodiments, the inhibitor of Ablim 3 is an inhibitory nucleicacid that is complementary to Ablim3. Exemplary inhibitory nucleic acidsfor use in the methods described herein include antisenseoligonucleotides and small interfering RNA, including but not limited toshRNA and siRNA. The sequence of Ablim3 is known in the art; in humans,there are 4 isoforms:

Isoform Nucleic Acid Protein Notes Isoform 1, NM_001301015.1NP_001287944.1 variant (1) represents the variant 1 longest transcriptand encodes the longest isoform (1). Both variants 1 and 2 encode thesame isoform 1 Isoform 1, NM_014945.3 NP_055760.1 variant (2) lacks aninternal variant 2 segment in the 5′ UTR, compared to variant 1. Bothvariants 1 and 2 encode the same isoform 1. Isoform 2, NM_001301018.1NP_001287947.1 variant (3) lacks an in-frame variant 3 exon in the 3′coding region, compared to variant 1. The resulting isoform (2) lacks aninternal segment, compared to isoform 1. Isoform 3, NM_001301027.1NP_001287956.1 variant (4) has an additional variant 4 exon in the 5′region, which results in translation initiation at a downstream startcodon, and lacks several in-frame exons in the 3′ coding region,compared to variant 1. The resulting isoform (3) has a distinct N-terminus and lacks two internal segments, compared to isoform 1. Isoform4, NM_001301028.1 NP_001287957.1 This variant (5) lacks several in-variant 5 frame exons and has an alternate splice site in the 3′ codingregion, compared to variant 1. The resulting isoform (4) lacks twointernal segments and has a shorter and distinct C- terminus, comparedto isoform 1.

Inhibitory Nucleic Acids

Inhibitory nucleic acids useful in the present methods and compositionsinclude antisense oligonucleotides, ribozymes, external guide sequence(EGS) oligonucleotides, siRNA compounds, single- or double-stranded RNAinterference (RNAi) compounds such as siRNA compounds, modifiedbases/locked nucleic acids (LNAs), peptide nucleic acids (PNAs), andother oligomeric compounds or oligonucleotide mimetics which hybridizeto at least a portion of the target nucleic acid and modulate itsfunction. In some embodiments, the inhibitory nucleic acids includeantisense RNA, antisense DNA, chimeric antisense oligonucleotides,antisense oligonucleotides comprising modified linkages, interferenceRNA (RNAi), short interfering RNA (siRNA); a micro, interfering RNA(miRNA); a small, temporal RNA (stRNA); or a short, hairpin RNA (shRNA);small RNA-induced gene activation (RNAa); small activating RNAs(saRNAs), or combinations thereof. See, e.g., WO 2010040112.

In some embodiments, the inhibitory nucleic acids are 10 to 50, 10 to20, 10 to 25, 13 to 50, or 13 to 30 nucleotides in length. One havingordinary skill in the art will appreciate that this embodies inhibitorynucleic acids having complementary portions of 10, 11, 12, 13, 14, 15,16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33,34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50nucleotides in length, or any range therewithin. In some embodiments,the inhibitory nucleic acids are 15 nucleotides in length. In someembodiments, the inhibitory nucleic acids are 12 or 13 to 20, 25, or 30nucleotides in length. One having ordinary skill in the art willappreciate that this embodies inhibitory nucleic acids havingcomplementary portions of 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25, 26, 27, 28, 29 or 30 nucleotides in length, or any rangetherewithin (complementary portions refers to those portions of theinhibitory nucleic acids that are complementary to the target sequence).

The inhibitory nucleic acids useful in the present methods aresufficiently complementary to the target RNA, i.e., hybridizesufficiently well and with sufficient specificity, to give the desiredeffect. “Complementary” refers to the capacity for pairing, throughhydrogen bonding, between two sequences comprising naturally ornon-naturally occurring bases or analogs thereof. For example, if a baseat one position of an inhibitory nucleic acid is capable of hydrogenbonding with a base at the corresponding position of a RNA, then thebases are considered to be complementary to each other at that position.100% complementarity is not required.

Routine methods can be used to design an inhibitory nucleic acid thatbinds to the Ablim3 sequence with sufficient specificity. In someembodiments, the methods include using bioinformatics methods known inthe art to identify regions of secondary structure, e.g., one, two, ormore stem-loop structures, or pseudoknots, and selecting those regionsto target with an inhibitory nucleic acid. For example, “gene walk”methods can be used to optimize the inhibitory activity of the nucleicacid; for example, a series of oligonucleotides of 10-30 nucleotidesspanning the length of a target RNA can be prepared, followed by testingfor activity. Optionally, gaps, e.g., of 5-10 nucleotides or more, canbe left between the target sequences to reduce the number ofoligonucleotides synthesized and tested. GC content is preferablybetween about 30-60%. Contiguous runs of three or more Gs or Cs shouldbe avoided where possible (for example, it may not be possible with veryshort (e.g., about 9-10 nt) oligonucleotides).

In some embodiments, the inhibitory nucleic acid molecules can bedesigned to target a specific region of the RNA sequence. For example, aspecific functional region can be targeted, e.g., a region comprising aknown RNA localization motif (i.e., a region complementary to the targetnucleic acid on which the RNA acts). Alternatively or in addition,highly conserved regions can be targeted, e.g., regions identified byaligning sequences from disparate species such as primate (e.g., human)and rodent (e.g., mouse) and looking for regions with high degrees ofidentity. Percent identity can be determined routinely using basic localalignment search tools (BLAST programs) (Altschul et al., J. Mol. Biol.,1990, 215, 403-410; Zhang and Madden, Genome Res., 1997, 7, 649-656),e.g., using the default parameters.

Once one or more target regions, segments or sites have been identified,e.g., within an Ablim3 sequence known in the art or provided herein,inhibitory nucleic acid compounds are chosen that are sufficientlycomplementary to the target, i.e., that hybridize sufficiently well andwith sufficient specificity (i.e., do not substantially bind to othernon-target RNAs), to give the desired effect.

In the context of this invention, hybridization means hydrogen bonding,which may be Watson-Crick, Hoogsteen or reversed Hoogsteen hydrogenbonding, between complementary nucleoside or nucleotide bases. Forexample, adenine and thymine are complementary nucleobases which pairthrough the formation of hydrogen bonds. Complementary, as used herein,refers to the capacity for precise pairing between two nucleotides. Forexample, if a nucleotide at a certain position of an oligonucleotide iscapable of hydrogen bonding with a nucleotide at the same position of aRNA molecule, then the inhibitory nucleic acid and the RNA areconsidered to be complementary to each other at that position. Theinhibitory nucleic acids and the RNA are complementary to each otherwhen a sufficient number of corresponding positions in each molecule areoccupied by nucleotides which can hydrogen bond with each other. Thus,“specifically hybridisable” and “complementary” are terms which are usedto indicate a sufficient degree of complementarity or precise pairingsuch that stable and specific binding occurs between the inhibitorynucleic acid and the RNA target. For example, if a base at one positionof an inhibitory nucleic acid is capable of hydrogen bonding with a baseat the corresponding position of a RNA, then the bases are considered tobe complementary to each other at that position. 100% complementarity isnot required.

It is understood in the art that a complementary nucleic acid sequenceneed not be 100% complementary to that of its target nucleic acid to bespecifically hybridisable. A complementary nucleic acid sequence forpurposes of the present methods is specifically hybridisable whenbinding of the sequence to the target RNA molecule interferes with thenormal function of the target RNA to cause a loss of activity, and thereis a sufficient degree of complementarity to avoid non-specific bindingof the sequence to non-target RNA sequences under conditions in whichspecific binding is desired, e.g., under physiological conditions in thecase of in vivo assays or therapeutic treatment, and in the case of invitro assays, under conditions in which the assays are performed undersuitable conditions of stringency. For example, stringent saltconcentration will ordinarily be less than about 750 mM NaCl and 75 mMtrisodium citrate, preferably less than about 500 mM NaCl and 50 mMtrisodium citrate, and more preferably less than about 250 mM NaCl and25 mM trisodium citrate. Low stringency hybridization can be obtained inthe absence of organic solvent, e.g., formamide, while high stringencyhybridization can be obtained in the presence of at least about 35%formamide, and more preferably at least about 50% formamide. Stringenttemperature conditions will ordinarily include temperatures of at leastabout 30° C., more preferably of at least about 37° C., and mostpreferably of at least about 42° C. Varying additional parameters, suchas hybridization time, the concentration of detergent, e.g., sodiumdodecyl sulfate (SDS), and the inclusion or exclusion of carrier DNA,are well known to those skilled in the art. Various levels of stringencyare accomplished by combining these various conditions as needed. In apreferred embodiment, hybridization will occur at 30° C. in 750 mM NaCl,75 mM trisodium citrate, and 1% SDS. In a more preferred embodiment,hybridization will occur at 37° C. in 500 mM NaCl, 50 mM trisodiumcitrate, 1% SDS, 35% formamide, and 100 μg/ml denatured salmon sperm DNA(ssDNA). In a most preferred embodiment, hybridization will occur at 42°C. in 250 mM NaCl, 25 mM trisodium citrate, 1% SDS, 50% formamide, and200 μg/ml ssDNA. Useful variations on these conditions will be readilyapparent to those skilled in the art.

For most applications, washing steps that follow hybridization will alsovary in stringency. Wash stringency conditions can be defined by saltconcentration and by temperature. As above, wash stringency can beincreased by decreasing salt concentration or by increasing temperature.For example, stringent salt concentration for the wash steps willpreferably be less than about 30 mM NaCl and 3 mM trisodium citrate, andmost preferably less than about 15 mM NaCl and 1.5 mM trisodium citrate.Stringent temperature conditions for the wash steps will ordinarilyinclude a temperature of at least about 25° C., more preferably of atleast about 42° C., and even more preferably of at least about 68° C. Ina preferred embodiment, wash steps will occur at 25° C. in 30 mM NaCl, 3mM trisodium citrate, and 0.1% SDS. In a more preferred embodiment, washsteps will occur at 42° C. in 15 mM NaCl, 1.5 mM trisodium citrate, and0.1% SDS. In a more preferred embodiment, wash steps will occur at 68°C. in 15 mM NaCl, 1.5 mM trisodium citrate, and 0.1% SDS. Additionalvariations on these conditions will be readily apparent to those skilledin the art. Hybridization techniques are well known to those skilled inthe art and are described, for example, in Benton and Davis (Science196:180, 1977); Grunstein and Hogness (Proc. Natl. Acad. Sci., USA72:3961, 1975); Ausubel et al. (Current Protocols in Molecular Biology,Wiley Interscience, New York, 2001); Berger and Kimmel (Guide toMolecular Cloning Techniques, 1987, Academic Press, New York); andSambrook et al., Molecular Cloning: A Laboratory Manual, Cold SpringHarbor Laboratory Press, New York.

In general, the inhibitory nucleic acids useful in the methods describedherein have at least 80% sequence complementarity to a target regionwithin the target nucleic acid, e.g., 90%, 95%, or 100% sequencecomplementarity to the target region within an RNA. For example, anantisense compound in which 18 of 20 nucleobases of the antisenseoligonucleotide are complementary, and would therefore specificallyhybridize, to a target region would represent 90 percentcomplementarity. Percent complementarity of an inhibitory nucleic acidwith a region of a target nucleic acid can be determined routinely usingbasic local alignment search tools (BLAST programs) (Altschul et al., J.Mol. Biol., 1990, 215, 403-410; Zhang and Madden, Genome Res., 1997, 7,649-656). Inhibitory nucleic acids that hybridize to an RNA can beidentified through routine experimentation. In general the inhibitorynucleic acids must retain specificity for their target, i.e., must notdirectly bind to, or directly significantly affect expression levels of,transcripts other than the intended target.

For further disclosure regarding inhibitory nucleic acids, please seeUS2010/0317718 (antisense oligos); US2010/0249052 (double-strandedribonucleic acid (dsRNA)); US2009/0181914 and US2010/0234451 (LNAs);US2007/0191294 (siRNA analogues); US2008/0249039 (modified siRNA); andWO2010/129746 and WO2010/040112 (inhibitory nucleic acids).

Antisense

In some embodiments, the inhibitory nucleic acids are antisenseoligonucleotides. Antisense oligonucleotides are typically designed toblock expression of a DNA or RNA target by binding to the target andhalting expression at the level of transcription, translation, orsplicing. Antisense oligonucleotides of the present invention arecomplementary nucleic acid sequences designed to hybridize understringent conditions to an RNA. Thus, oligonucleotides are chosen thatare sufficiently complementary to the target, i.e., that hybridizesufficiently well and with sufficient specificity, to give the desiredeffect.

siRNA/shRNA

In some embodiments, the nucleic acid sequence that is complementary toan Ablim3 RNA can be an interfering RNA, including but not limited to asmall interfering RNA (“siRNA”) or a small hairpin RNA (“shRNA”).Methods for constructing interfering RNAs are well known in the art. Forexample, the interfering RNA can be assembled from two separateoligonucleotides, where one strand is the sense strand and the other isthe antisense strand, wherein the antisense and sense strands areself-complementary (i.e., each strand comprises nucleotide sequence thatis complementary to nucleotide sequence in the other strand; such aswhere the antisense strand and sense strand form a duplex or doublestranded structure); the antisense strand comprises nucleotide sequencethat is complementary to a nucleotide sequence in a target nucleic acidmolecule or a portion thereof (i.e., an undesired gene) and the sensestrand comprises nucleotide sequence corresponding to the target nucleicacid sequence or a portion thereof. Alternatively, interfering RNA isassembled from a single oligonucleotide, where the self-complementarysense and antisense regions are linked by means of nucleic acid based ornon-nucleic acid-based linker(s). The interfering RNA can be apolynucleotide with a duplex, asymmetric duplex, hairpin or asymmetrichairpin secondary structure, having self-complementary sense andantisense regions, wherein the antisense region comprises a nucleotidesequence that is complementary to nucleotide sequence in a separatetarget nucleic acid molecule or a portion thereof and the sense regionhaving nucleotide sequence corresponding to the target nucleic acidsequence or a portion thereof. The interfering can be a circularsingle-stranded polynucleotide having two or more loop structures and astem comprising self-complementary sense and antisense regions, whereinthe antisense region comprises nucleotide sequence that is complementaryto nucleotide sequence in a target nucleic acid molecule or a portionthereof and the sense region having nucleotide sequence corresponding tothe target nucleic acid sequence or a portion thereof, and wherein thecircular polynucleotide can be processed either in vivo or in vitro togenerate an active siRNA molecule capable of mediating RNA interference.

In some embodiments, the interfering RNA coding region encodes aself-complementary RNA molecule having a sense region, an antisenseregion and a loop region. Such an RNA molecule when expressed desirablyforms a “hairpin” structure, and is referred to herein as an “shRNA.”The loop region is generally between about 2 and about 10 nucleotides inlength. In some embodiments, the loop region is from about 6 to about 9nucleotides in length. In some embodiments, the sense region and theantisense region are between about 15 and about 20 nucleotides inlength. Following post-transcriptional processing, the small hairpin RNAis converted into a siRNA by a cleavage event mediated by the enzymeDicer, which is a member of the RNase III family. The siRNA is thencapable of inhibiting the expression of a gene with which it shareshomology. For details, see Brummelkamp et al., Science 296:550-553,(2002); Lee et al, Nature Biotechnol., 20, 500-505, (2002); Miyagishiand Taira, Nature Biotechnol 20:497-500, (2002); Paddison et al. Genes &Dev. 16:948-958, (2002); Paul, Nature Biotechnol, 20, 505-508, (2002);Sui, Proc. Natl. Acad. Sd. USA, 99(6), 5515-5520, (2002); Yu et al. ProcNatlAcadSci USA 99:6047-6052, (2002).

The target RNA cleavage reaction guided by siRNAs is highly sequencespecific. In general, siRNA containing a nucleotide sequences identicalto a portion of the target nucleic acid are preferred for inhibition.However, 100% sequence identity between the siRNA and the target gene isnot required to practice the present invention. Thus the invention hasthe advantage of being able to tolerate sequence variations that mightbe expected due to genetic mutation, strain polymorphism, orevolutionary divergence. For example, siRNA sequences with insertions,deletions, and single point mutations relative to the target sequencehave also been found to be effective for inhibition. Alternatively,siRNA sequences with nucleotide analog substitutions or insertions canbe effective for inhibition. In general the siRNAs must retainspecificity for their target, i.e., must not directly bind to, ordirectly significantly affect expression levels of, transcripts otherthan the intended target.

Ribozymes

Trans-cleaving enzymatic nucleic acid molecules can also be used; theyhave shown promise as therapeutic agents for human disease (Usman &McSwiggen, 1995 Ann. Rep. Med. Chem. 30, 285-294; Christoffersen andMarr, 1995 J. Med. Chem. 38, 2023-2037). Enzymatic nucleic acidmolecules can be designed to cleave specific RNA targets within thebackground of cellular RNA. Such a cleavage event renders the RNAnon-functional.

In general, enzymatic nucleic acids with RNA cleaving activity act byfirst binding to a target RNA. Such binding occurs through the targetbinding portion of a enzymatic nucleic acid which is held in closeproximity to an enzymatic portion of the molecule that acts to cleavethe target RNA. Thus, the enzymatic nucleic acid first recognizes andthen binds a target RNA through complementary base pairing, and oncebound to the correct site, acts enzymatically to cut the target RNA.Strategic cleavage of such a target RNA will destroy its ability todirect synthesis of an encoded protein. After an enzymatic nucleic acidhas bound and cleaved its RNA target, it is released from that RNA tosearch for another target and can repeatedly bind and cleave newtargets.

Several approaches such as in vitro selection (evolution) strategies(Orgel, 1979, Proc. R. Soc. London, B 205, 435) have been used to evolvenew nucleic acid catalysts capable of catalyzing a variety of reactions,such as cleavage and ligation of phosphodiester linkages and amidelinkages, (Joyce, 1989, Gene, 82, 83-87; Beaudry et al., 1992, Science257, 635-641; Joyce, 1992, Scientific American 267, 90-97; Breaker etal, 1994, TIBTECH 12, 268; Bartel et al, 1993, Science 261 :1411-1418;Szostak, 1993, TIBS 17, 89-93; Kumar et al, 1995, FASEB J., 9, 1183;Breaker, 1996, Curr. Op. Biotech., 1, 442). The development of ribozymesthat are optimal for catalytic activity would contribute significantlyto any strategy that employs RNA-cleaving ribozymes for the purpose ofregulating gene expression. The hammerhead ribozyme, for example,functions with a catalytic rate (kcat) of about 1 min⁻¹ in the presenceof saturating (10 rnM) concentrations of Mg²⁺ cofactor. An artificial“RNA ligase” ribozyme has been shown to catalyze the correspondingself-modification reaction with a rate of about 100 min⁻¹. In addition,it is known that certain modified hammerhead ribozymes that havesubstrate binding arms made of DNA catalyze RNA cleavage with multipleturn-over rates that approach 100 min⁻¹.

Modified Inhibitory Nucleic Acids

In some embodiments, the inhibitory nucleic acids used in the methodsdescribed herein are modified, e.g., comprise one or more modified bondsor bases. A number of modified bases include phosphorothioate,methylphosphonate, peptide nucleic acids, or locked nucleic acid (LNA)molecules. Some inhibitory nucleic acids are fully modified, whileothers are chimeric and contain two or more chemically distinct regions,each made up of at least one nucleotide. These inhibitory nucleic acidstypically contain at least one region of modified nucleotides thatconfers one or more beneficial properties (such as, for example,increased nuclease resistance, increased uptake into cells, increasedbinding affinity for the target) and a region that is a substrate forenzymes capable of cleaving RNA:DNA or RNA:RNA hybrids. Chimericinhibitory nucleic acids of the invention may be formed as compositestructures of two or more oligonucleotides, modified oligonucleotides,oligonucleosides and/or oligonucleotide mimetics as described above.Such compounds have also been referred to in the art as hybrids orgapmers. Representative United States patents that teach the preparationof such hybrid structures comprise, but are not limited to, U.S. Pat.Nos. 5,013,830; 5,149,797; 5,220,007; 5,256,775; 5,366,878; 5,403,711;5,491,133; 5,565,350; 5,623,065; 5,652,355; 5,652,356; and 5,700,922,each of which is herein incorporated by reference.

In some embodiments, the inhibitory nucleic acid comprises at least onenucleotide modified at the 2′ position of the sugar, most preferably a2′-O-alkyl, 2′-O-alkyl-O-alkyl or 2′-fluoro-modified nucleotide. Inother preferred embodiments, RNA modifications include 2′-fluoro,2′-amino and 2′ O-methyl modifications on the ribose of pyrimidines,abasic residues or an inverted base at the 3′ end of the RNA. Suchmodifications are routinely incorporated into oligonucleotides and theseoligonucleotides have been shown to have a higher Tm (i.e., highertarget binding affinity) than; 2′-deoxyoligonucleotides against a giventarget.

A number of nucleotide and nucleoside modifications have been shown tomake the oligonucleotide into which they are incorporated more resistantto nuclease digestion than the native oligodeoxynucleotide; thesemodified oligos survive intact for a longer time than unmodifiedoligonucleotides. Specific examples of modified oligonucleotides includethose comprising modified backbones, for example, phosphorothioates,phosphotriesters, methyl phosphonates, short chain alkyl or cycloalkylintersugar linkages or short chain heteroatomic or heterocyclicintersugar linkages. Most preferred are oligonucleotides withphosphorothioate backbones and those with heteroatom backbones,particularly CH2-NH—O—CH2, CH, ˜N(CH3)˜O˜CH2 (known as amethylene(methylimino) or MMI backbone], CH2-O—N(CH3)-CH2,CH2-N(CH3)-N(CH3)-CH2 and O—N(CH3)-CH2-CH2 backbones, wherein the nativephosphodiester backbone is represented as O—P—O—CH,); amide backbones(see De Mesmaeker et al. Ace. Chem. Res. 1995, 28:366-374); morpholinobackbone structures (see Summerton and Weller, U.S. Pat. No. 5,034,506);peptide nucleic acid (PNA) backbone (wherein the phosphodiester backboneof the oligonucleotide is replaced with a polyamide backbone, thenucleotides being bound directly or indirectly to the aza nitrogen atomsof the polyamide backbone, see Nielsen et al., Science 1991, 254, 1497).Phosphorus-containing linkages include, but are not limited to,phosphorothioates, chiral phosphorothioates, phosphorodithioates,phosphotriesters, aminoalkylphosphotriesters, methyl and other alkylphosphonates comprising 3′alkylene phosphonates and chiral phosphonates,phosphinates, phosphoramidates comprising 3′-amino phosphoramidate andaminoalkylphosphoramidates, thionophosphoramidates,thionoalkylphosphonates, thionoalkylphosphotriesters, andboranophosphates having normal 3′-5′ linkages, 2′-5′ linked analogs ofthese, and those having inverted polarity wherein the adjacent pairs ofnucleoside units are linked 3′-5′ to 5′-3′ or 2′-5′ to 5′-2′; see U.S.Pat. Nos. 3,687,808; 4,469,863; 4,476,301; 5,023,243; 5, 177,196;5,188,897; 5,264,423; 5,276,019; 5,278,302; 5,286,717; 5,321,131;5,399,676; 5,405,939; 5,453,496; 5,455, 233; 5,466,677; 5,476,925;5,519,126; 5,536,821; 5,541,306; 5,550,111; 5,563, 253; 5,571,799;5,587,361; and 5,625,050.

Morpholino-based oligomeric compounds are described in Dwaine A. Braaschand David R. Corey, Biochemistry, 2002, 41(14), 4503-4510); Genesis,volume 30, issue 3, 2001; Heasman, J., Dev. Biol., 2002, 243, 209-214;Nasevicius et al., Nat. Genet., 2000, 26, 216-220; Lacerra et al., Proc.Natl. Acad. Sci., 2000, 97, 9591-9596; and U.S. Pat. No. 5,034,506,issued Jul. 23, 1991.

Cyclohexenyl nucleic acid oligonucleotide mimetics are described in Wanget al., J. Am. Chem. Soc., 2000, 122, 8595-8602.

Modified oligonucleotide backbones that do not include a phosphorus atomtherein have backbones that are formed by short chain alkyl orcycloalkyl internucleoside linkages, mixed heteroatom and alkyl orcycloalkyl internucleoside linkages, or one or more short chainheteroatomic or heterocyclic internucleoside linkages. These comprisethose having morpholino linkages (formed in part from the sugar portionof a nucleoside); siloxane backbones; sulfide, sulfoxide and sulfonebackbones; formacetyl and thioformacetyl backbones; methylene formacetyland thioformacetyl backbones; alkene containing backbones; sulfamatebackbones; methyleneimino and methylenehydrazino backbones; sulfonateand sulfonamide backbones; amide backbones; and others having mixed N,O, S and CH2 component parts; see U.S. Pat. Nos. 5,034,506; 5,166,315;5,185,444; 5,214,134; 5,216,141; 5,235,033; 5,264,562; 5,264,564;5,405,938; 5,434,257; 5,466,677; 5,470,967; 5,489,677; 5,541,307;5,561,225; 5,596, 086; 5,602,240; 5,610,289; 5,602,240; 5,608,046;5,610,289; 5,618,704; 5,623,070; 5,663,312; 5,633,360; 5,677,437; and5,677,439, each of which is herein incorporated by reference.

One or more substituted sugar moieties can also be included, e.g., oneof the following at the 2′ position: OH, SH, SCH₃, F, OCN, OCH₃OCH₃,OCH₃O(CH₂)n CH₃, O(CH₂)nNH₂ or O(CH₂)nCH₃ where n is from 1 to about 10;Ci to C10 lower alkyl, alkoxyalkoxy, substituted lower alkyl, alkaryl oraralkyl; Cl; Br; CN; CF3; OCF3; O-, S-, or N-alkyl; O-, S-, orN-alkenyl; SOCH3; SO2CH3; ONO2; NO2; N3; NH2; heterocycloalkyl;heterocycloalkaryl; aminoalkylamino; polyalkylamino; substituted silyl;an RNA cleaving group; a reporter group; an intercalator; a group forimproving the pharmacokinetic properties of an oligonucleotide; or agroup for improving the pharmacodynamic properties of an oligonucleotideand other substituents having similar properties. A preferredmodification includes 2′-methoxyethoxy [2′-0-CH₂CH₂OCH₃, also known as2′-O-(2-methoxyethyl)] (Martin et al, Helv. Chim. Acta, 1995, 78, 486).Other preferred modifications include 2′-methoxy (2′-0-CH₃), 2′-propoxy(2′-OCH₂CH₂CH₃) and 2′-fluoro (2′-F). Similar modifications may also bemade at other positions on the oligonucleotide, particularly the 3′position of the sugar on the 3′ terminal nucleotide and the 5′ positionof 5′ terminal nucleotide. Oligonucleotides may also have sugar mimeticssuch as cyclobutyls in place of the pentofuranosyl group.

Inhibitory nucleic acids can also include, additionally oralternatively, nucleobase (often referred to in the art simply as“base”) modifications or substitutions. As used herein, “unmodified” or“natural” nucleobases include adenine (A), guanine (G), thymine (T),cytosine (C) and uracil (U). Modified nucleobases include nucleobasesfound only infrequently or transiently in natural nucleic acids, e.g.,hypoxanthine, 6-methyladenine, 5-Me pyrimidines, particularly5-methylcytosine (also referred to as 5-methyl-2′ deoxycytosine andoften referred to in the art as 5-Me-C), 5-hydroxymethylcytosine (HMC),glycosyl HMC and gentobiosyl HMC, as well as synthetic nucleobases,e.g., 2-aminoadenine, 2-(methylamino)adenine,2-(imidazolylalkyl)adenine, 2-(aminoalklyamino)adenine or otherheterosubstituted alkyladenines, 2-thiouracil, 2-thiothymine,5-bromouracil, 5-hydroxymethyluracil, 8-azaguanine, 7-deazaguanine, N6(6-aminohexyl)adenine and 2,6-diaminopurine. Kornberg, A., DNAReplication, W. H. Freeman & Co., San Francisco, 1980, pp 75-77;Gebeyehu, G., et al. Nucl. Acids Res. 1987, 15:4513). A “universal” baseknown in the art, e.g., inosine, can also be included. 5-Me-Csubstitutions have been shown to increase nucleic acid duplex stabilityby 0.6-1.2<0>C. (Sanghvi, Y. S., in Crooke, S. T. and Lebleu, B., eds.,Antisense Research and Applications, CRC Press, Boca Raton, 1993, pp.276-278) and are presently preferred base substitutions.

It is not necessary for all positions in a given oligonucleotide to beuniformly modified, and in fact more than one of the aforementionedmodifications may be incorporated in a single oligonucleotide or even atwithin a single nucleoside within an oligonucleotide.

In some embodiments, both a sugar and an internucleoside linkage, i.e.,the backbone, of the nucleotide units are replaced with novel groups.The base units are maintained for hybridization with an appropriatenucleic acid target compound. One such oligomeric compound, anoligonucleotide mimetic that has been shown to have excellenthybridization properties, is referred to as a peptide nucleic acid(PNA). In PNA compounds, the sugar-backbone of an oligonucleotide isreplaced with an amide containing backbone, for example, anaminoethylglycine backbone. The nucleobases are retained and are bounddirectly or indirectly to aza nitrogen atoms of the amide portion of thebackbone. Representative United States patents that teach thepreparation of PNA compounds comprise, but are not limited to, U.S. Pat.Nos. 5,539,082; 5,714,331; and 5,719,262, each of which is hereinincorporated by reference. Further teaching of PNA compounds can befound in Nielsen et al, Science, 1991, 254, 1497-1500.

Inhibitory nucleic acids can also include one or more nucleobase (oftenreferred to in the art simply as “base”) modifications or substitutions.As used herein, “unmodified” or “natural” nucleobases comprise thepurine bases adenine (A) and guanine (G), and the pyrimidine basesthymine (T), cytosine (C) and uracil (U). Modified nucleobases compriseother synthetic and natural nucleobases such as 5-methylcytosine(5-me-C), 5-hydroxymethyl cytosine, xanthine, hypoxanthine,2-aminoadenine, 6-methyl and other alkyl derivatives of adenine andguanine, 2-propyl and other alkyl derivatives of adenine and guanine,2-thiouracil, 2-thiothymine and 2-thiocytosine, 5-halouracil andcytosine, 5-propynyl uracil and cytosine, 6-azo uracil, cytosine andthymine, 5-uracil (pseudo-uracil), 4-thiouracil, 8-halo, 8-amino,8-thiol, 8-thioalkyl, 8-hydroxyl and other 8-substituted adenines andguanines, 5-halo particularly 5-bromo, 5-trifluoromethyl and other5-substituted uracils and cytosines, 7-methylquanine and7-methyladenine, 8-azaguanine and 8-azaadenine, 7-deazaguanine and7-deazaadenine and 3-deazaguanine and 3-deazaadenine.

Further, nucleobases comprise those disclosed in U.S. Pat. No.3,687,808, those disclosed in ‘The Concise Encyclopedia of PolymerScience And Engineering’, pages 858-859, Kroschwitz, J. I., ed. JohnWiley & Sons, 1990, those disclosed by Englisch et al., AngewandleChemie, International Edition’, 1991, 30, page 613, and those disclosedby Sanghvi, Y. S., Chapter 15, Antisense Research and Applications’,pages 289-302, Crooke, S. T. and Lebleu, B. ea., CRC Press, 1993.Certain of these nucleobases are particularly useful for increasing thebinding affinity of the oligomeric compounds of the invention. Theseinclude 5-substituted pyrimidines, 6-azapyrimidines and N-2, N-6 and 0-6substituted purines, comprising 2-aminopropyladenine, 5-propynyluraciland 5-propynylcytosine. 5-methylcytosine substitutions have been shownto increase nucleic acid duplex stability by 0.6-1.2<0>C (Sanghvi, Y.S., Crooke, S. T. and Lebleu, B., eds, ‘Antisense Research andApplications’, CRC Press, Boca Raton, 1993, pp. 276-278) and arepresently preferred base substitutions, even more particularly whencombined with 2′-O-methoxyethyl sugar modifications. Modifiednucleobases are described in U.S. Pat. No. 3,687,808, as well as U.S.Pat. Nos. 4,845,205; 5,130,302; 5,134,066; 5,175, 273; 5,367,066;5,432,272; 5,457,187; 5,459,255; 5,484,908; 5,502,177; 5,525,711;5,552,540; 5,587,469; 5,596,091; 5,614,617; 5,750,692, and 5,681,941,each of which is herein incorporated by reference.

In some embodiments, the inhibitory nucleic acids are chemically linkedto one or more moieties or conjugates that enhance the activity,cellular distribution, or cellular uptake of the oligonucleotide. Suchmoieties comprise but are not limited to, lipid moieties such as acholesterol moiety (Letsinger et al., Proc. Natl. Acad. Sci. USA, 1989,86, 6553-6556), cholic acid (Manoharan et al., Bioorg. Med. Chem. Let.,1994, 4, 1053-1060), a thioether, e.g., hexyl-S-tritylthiol (Manoharanet al, Ann. N. Y. Acad. Sci., 1992, 660, 306-309; Manoharan et al.,Bioorg. Med. Chem. Let., 1993, 3, 2765-2770), a thiocholesterol(Oberhauser et al., Nucl. Acids Res., 1992, 20, 533-538), an aliphaticchain, e.g., dodecandiol or undecyl residues (Kabanov et al., FEBSLett., 1990, 259, 327-330; Svinarchuk et al., Biochimie, 1993, 75,49-54), a phospholipid, e.g., di-hexadecyl-rac-glycerol ortriethylammonium 1,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate(Manoharan et al., Tetrahedron Lett., 1995, 36, 3651-3654; Shea et al.,Nucl. Acids Res., 1990, 18, 3777-3783), a polyamine or a polyethyleneglycol chain (Mancharan et al., Nucleosides & Nucleotides, 1995, 14,969-973), or adamantane acetic acid (Manoharan et al., TetrahedronLett., 1995, 36, 3651-3654), a palmityl moiety (Mishra et al., Biochim.Biophys. Acta, 1995, 1264, 229-237), or an octadecylamine orhexylamino-carbonyl-t oxycholesterol moiety (Crooke et al., J.Pharmacol. Exp. Ther., 1996, 277, 923-937). See also U.S. Pat. Nos.4,828,979; 4,948,882; 5,218,105; 5,525,465; 5,541,313; 5,545,730;5,552,538; 5,578,717, 5,580,731; 5,580,731; 5,591,584; 5,109,124;5,118,802; 5,138,045; 5,414,077; 5,486,603; 5,512,439; 5,578,718;5,608,046; 4,587,044; 4,605,735; 4,667,025; 4,762,779; 4,789,737;4,824,941; 4,835,263; 4,876,335; 4,904,582; 4,958,013; 5,082,830;5,112,963; 5,214,136; 5,082,830; 5,112,963; 5,214,136; 5,245,022;5,254,469; 5,258,506; 5,262,536; 5,272,250; 5,292,873; 5,317,098;5,371,241, 5,391, 723; 5,416,203, 5,451,463; 5,510,475; 5,512,667;5,514,785; 5, 565,552; 5,567,810; 5,574,142; 5,585,481; 5,587,371;5,595,726; 5,597,696; 5,599,923; 5,599,928 and 5,688,941, each of whichis herein incorporated by reference.

These moieties or conjugates can include conjugate groups covalentlybound to functional groups such as primary or secondary hydroxyl groups.Conjugate groups of the invention include intercalators, reportermolecules, polyamines, polyamides, polyethylene glycols, polyethers,groups that enhance the pharmacodynamic properties of oligomers, andgroups that enhance the pharmacokinetic properties of oligomers. Typicalconjugate groups include cholesterols, lipids, phospholipids, biotin,phenazine, folate, phenanthridine, anthraquinone, acridine,fluoresceins, rhodamines, coumarins, and dyes. Groups that enhance thepharmacodynamic properties, in the context of this invention, includegroups that improve uptake, enhance resistance to degradation, and/orstrengthen sequence-specific hybridization with the target nucleic acid.Groups that enhance the pharmacokinetic properties, in the context ofthis invention, include groups that improve uptake, distribution,metabolism or excretion of the compounds of the present invention.Representative conjugate groups are disclosed in International PatentApplication No. PCT/US92/09196, filed Oct. 23, 1992, and U.S. Pat. No.6,287,860, which are incorporated herein by reference. Conjugatemoieties include, but are not limited to, lipid moieties such as acholesterol moiety, cholic acid, a thioether, e.g., hexyl-5-tritylthiol,a thiocholesterol, an aliphatic chain, e.g., dodecandiol or undecylresidues, a phospholipid, e.g., di-hexadecyl-rac-glycerol ortriethylammoniuml,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate, apolyamine or a polyethylene glycol chain, or adamantane acetic acid, apalmityl moiety, or an octadecylamine or hexylamino-carbonyl-oxycholesterol moiety. See, e.g., U.S. Pat. Nos. 4,828,979; 4,948,882;5,218,105; 5,525,465; 5,541,313; 5,545,730; 5,552,538; 5,578,717,5,580,731; 5,580,731; 5,591,584; 5,109,124; 5,118,802; 5,138,045;5,414,077; 5,486,603; 5,512,439; 5,578,718; 5,608,046; 4,587,044;4,605,735; 4,667,025; 4,762,779; 4,789,737; 4,824,941; 4,835,263;4,876,335; 4,904,582; 4,958,013; 5,082,830; 5,112,963; 5,214,136;5,082,830; 5,112,963; 5,214,136; 5,245,022; 5,254,469; 5,258,506;5,262,536; 5,272,250; 5,292,873; 5,317,098; 5,371,241, 5,391,723;5,416,203, 5,451,463; 5,510,475; 5,512,667; 5,514,785; 5,565,552;5,567,810; 5,574,142; 5,585,481; 5,587,371; 5,595,726; 5,597,696;5,599,923; 5,599,928 and 5,688,941.

Locked Nucleic Acids (LNAs)

In some embodiments, the modified inhibitory nucleic acids used in themethods described herein comprise locked nucleic acid (LNA) molecules,e.g., including [alpha]-L-LNAs. LNAs comprise ribonucleic acid analogueswherein the ribose ring is “locked” by a methylene bridge between the2′-oxgygen and the 4′-carbon—i.e., oligonucleotides containing at leastone LNA monomer, that is, one 2′-O,4′-C-methylene-β-D-ribofuranosylnucleotide. LNA bases form standard Watson-Crick base pairs but thelocked configuration increases the rate and stability of the basepairingreaction (Jepsen et al., Oligonucleotides, 14, 130-146 (2004)). LNAsalso have increased affinity to base pair with RNA as compared to DNA.These properties render LNAs especially useful as probes forfluorescence in situ hybridization (FISH) and comparative genomichybridization, as knockdown tools for miRNAs, and as antisenseoligonucleotides to target mRNAs or other RNAs, e.g., RNAs as describedherien.

The LNA molecules can include molecules comprising 10-30, e.g., 12-24,e.g., 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,28, 29, or 30 nucleotides in each strand, wherein one of the strands issubstantially identical, e.g., at least 80% (or more, e.g., 85%, 90%,95%, or 100%) identical, e.g., having 3, 2, 1, or 0 mismatchednucleotide(s), to a target region in the RNA. The LNA molecules can bechemically synthesized using methods known in the art.

The LNA molecules can be designed using any method known in the art; anumber of algorithms are known, and are commercially available (e.g., onthe internet, for example at exiqon.com). See, e.g., You et al., Nuc.Acids. Res. 34:e60 (2006); McTigue et al., Biochemistry 43:5388-405(2004); and Levin et al., Nuc. Acids. Res. 34:e142 (2006). For example,“gene walk” methods, similar to those used to design antisense oligos,can be used to optimize the inhibitory activity of the LNA; for example,a series of oligonucleotides of 10-30 nucleotides spanning the length ofa target RNA can be prepared, followed by testing for activity.Optionally, gaps, e.g., of 5-10 nucleotides or more, can be left betweenthe LNAs to reduce the number of oligonucleotides synthesized andtested. GC content is preferably between about 30-60%. Generalguidelines for designing LNAs are known in the art; for example, LNAsequences will bind very tightly to other LNA sequences, so it ispreferable to avoid significant complementarity within an LNA.Contiguous runs of more than four LNA residues, should be avoided wherepossible (for example, it may not be possible with very short (e.g.,about 9-10 nt) oligonucleotides). In some embodiments, the LNAs arexylo-LNAs.

For additional information regarding LNAs see U.S. Pat. Nos. 6,268,490;6,734,291; 6,770,748; 6,794,499; 7,034,133; 7,053,207; 7,060,809;7,084,125; and 7,572,582; and U.S. Pre-Grant Pub. Nos. 20100267018;20100261175; and 20100035968; Koshkin et al. Tetrahedron 54, 3607-3630(1998); Obika et al. Tetrahedron Lett. 39, 5401-5404 (1998); Jepsen etal., Oligonucleotides 14:130-146 (2004); Kauppinen et al., Drug Disc.Today 2(3):287-290 (2005); and Ponting et al., Cell 136(4):629-641(2009), and references cited therein.

Making and Using Inhibitory Nucleic Acids

The nucleic acid sequences used to practice the methods describedherein, whether RNA, cDNA, genomic DNA, vectors, viruses or hybridsthereof, can be isolated from a variety of sources, geneticallyengineered, amplified, and/or expressed/generated recombinantly.Recombinant nucleic acid sequences can be individually isolated orcloned and tested for a desired activity. Any recombinant expressionsystem can be used, including e.g. in vitro, bacterial, fungal,mammalian, yeast, insect or plant cell expression systems.

Nucleic acid sequences of the invention can be inserted into deliveryvectors and expressed from transcription units within the vectors. Therecombinant vectors can be DNA plasmids or viral vectors. Generation ofthe vector construct can be accomplished using any suitable geneticengineering techniques well known in the art, including, withoutlimitation, the standard techniques of PCR, oligonucleotide synthesis,restriction endonuclease digestion, ligation, transformation, plasmidpurification, and DNA sequencing, for example as described in Sambrooket al. Molecular Cloning: A Laboratory Manual. (1989)), Coffin et al.(Retroviruses. (1997)) and “RNA Viruses: A Practical Approach” (Alan J.Cann, Ed., Oxford University Press, (2000)). As will be apparent to oneof ordinary skill in the art, a variety of suitable vectors areavailable for transferring nucleic acids of the invention into cells.The selection of an appropriate vector to deliver nucleic acids andoptimization of the conditions for insertion of the selected expressionvector into the cell, are within the scope of one of ordinary skill inthe art without the need for undue experimentation. Viral vectorscomprise a nucleotide sequence having sequences for the production ofrecombinant virus in a packaging cell. Viral vectors expressing nucleicacids of the invention can be constructed based on viral backbonesincluding, but not limited to, a retrovirus, lentivirus, adenovirus,adeno-associated virus, pox virus or alphavirus. The recombinant vectorscapable of expressing the nucleic acids of the invention can bedelivered as described herein, and persist in target cells (e.g., stabletransformants).

Nucleic acid sequences used to practice this invention can besynthesized in vitro by well-known chemical synthesis techniques, asdescribed in, e.g., Adams (1983) J. Am. Chem. Soc. 105:661; Belousov(1997) Nucleic Acids Res. 25:3440-3444; Frenkel (1995) Free Radic. Biol.Med. 19:373-380; Blommers (1994) Biochemistry 33:7886-7896; Narang(1979) Meth. Enzymol. 68:90; Brown (1979) Meth. Enzymol. 68:109;Beaucage (1981) Tetra. Lett. 22:1859; U.S. Pat. No. 4,458,066.

Nucleic acid sequences of the invention can be stabilized againstnucleolytic degradation such as by the incorporation of a modification,e.g., a nucleotide modification. For example, nucleic acid sequences ofthe invention includes a phosphorothioate at least the first, second, orthird internucleotide linkage at the 5′ or 3′ end of the nucleotidesequence. As another example, the nucleic acid sequence can include a2′-modified nucleotide, e.g., a 2′-deoxy, 2′-deoxy-2′-fluoro,2′-O-methyl, 2′-O-methoxyethyl (2′-O-MOE), 2′-O-aminopropyl (2′-O-AP),2′-O-dimethylaminoethyl (2′-O-DMAOE), 2′-O-dimethylaminopropyl(2′-O-DMAP), 2′-O-dimethylaminoethyloxyethyl (2′-O-DMAEOE), or2′-O—N-methylacetamido (2′-O—NMA). As another example, the nucleic acidsequence can include at least one 2′-O-methyl-modified nucleotide, andin some embodiments, all of the nucleotides include a 2′-O-methylmodification. In some embodiments, the nucleic acids are “locked,” i.e.,comprise nucleic acid analogues in which the ribose ring is “locked” bya methylene bridge connecting the 2′-O atom and the 4′-C atom (see,e.g., Kaupinnen et al., Drug Disc. Today 2(3):287-290 (2005); Koshkin etal., J. Am. Chem. Soc., 120(50):13252-13253 (1998)). For additionalmodifications see US 20100004320, US 20090298916, and US 20090143326.

Techniques for the manipulation of nucleic acids used to practice thisinvention, such as, e.g., subcloning, labeling probes (e.g.,random-primer labeling using Klenow polymerase, nick translation,amplification), sequencing, hybridization and the like are welldescribed in the scientific and patent literature, see, e.g., Sambrooket al., Molecular Cloning; A Laboratory Manual 3d ed. (2001); CurrentProtocols in Molecular Biology, Ausubel et al., eds. (John Wiley & Sons,Inc., New York 2010); Kriegler, Gene Transfer and Expression: ALaboratory Manual (1990); Laboratory Techniques In Biochemistry AndMolecular Biology: Hybridization With Nucleic Acid Probes, Part I.Theory and Nucleic Acid Preparation, Tijssen, ed. Elsevier, N.Y. (1993).

Pharmaceutical Compositions

The methods described herein can include the administration ofpharmaceutical compositions and formulations comprising inhibitorynucleic acid sequences designed to target an RNA.

In some embodiments, the compositions are formulated with apharmaceutically acceptable carrier. The pharmaceutical compositions andformulations can be administered parenterally, topically, orally or bylocal administration, such as by aerosol or transdermally. Thepharmaceutical compositions can be formulated in any way and can beadministered in a variety of unit dosage forms depending upon thecondition or disease and the degree of illness, the general medicalcondition of each patient, the resulting preferred method ofadministration and the like. Details on techniques for formulation andadministration of pharmaceuticals are well described in the scientificand patent literature, see, e.g., Remington: The Science and Practice ofPharmacy, 21st ed., 2005.

The inhibitory nucleic acids can be administered alone or as a componentof a pharmaceutical formulation (composition). The compounds may beformulated for administration, in any convenient way for use in human orveterinary medicine. Wetting agents, emulsifiers and lubricants, such assodium lauryl sulfate and magnesium stearate, as well as coloringagents, release agents, coating agents, sweetening, flavoring andperfuming agents, preservatives and antioxidants can also be present inthe compositions.

Formulations of the compositions of the invention include those suitablefor intradermal, inhalation, oral/nasal, topical, parenteral, rectal,and/or intravaginal administration. The formulations may conveniently bepresented in unit dosage form and may be prepared by any methods wellknown in the art of pharmacy. The amount of active ingredient (e.g.,nucleic acid sequences of this invention) which can be combined with acarrier material to produce a single dosage form will vary dependingupon the host being treated, the particular mode of administration,e.g., intradermal or inhalation. The amount of active ingredient whichcan be combined with a carrier material to produce a single dosage formwill generally be that amount of the compound which produces atherapeutic effect, e.g., an antigen specific T cell or humoralresponse.

Pharmaceutical formulations can be prepared according to any methodknown to the art for the manufacture of pharmaceuticals. Such drugs cancontain sweetening agents, flavoring agents, coloring agents andpreserving agents. A formulation can be admixtured with nontoxicpharmaceutically acceptable excipients which are suitable formanufacture. Formulations may comprise one or more diluents,emulsifiers, preservatives, buffers, excipients, etc. and may beprovided in such forms as liquids, powders, emulsions, lyophilizedpowders, sprays, creams, lotions, controlled release formulations,tablets, pills, gels, on patches, in implants, etc.

Pharmaceutical formulations for oral administration can be formulatedusing pharmaceutically acceptable carriers well known in the art inappropriate and suitable dosages. Such carriers enable thepharmaceuticals to be formulated in unit dosage forms as tablets, pills,powder, dragees, capsules, liquids, lozenges, gels, syrups, slurries,suspensions, etc., suitable for ingestion by the patient. Pharmaceuticalpreparations for oral use can be formulated as a solid excipient,optionally grinding a resulting mixture, and processing the mixture ofgranules, after adding suitable additional compounds, if desired, toobtain tablets or dragee cores. Suitable solid excipients arecarbohydrate or protein fillers include, e.g., sugars, includinglactose, sucrose, mannitol, or sorbitol; starch from corn, wheat, rice,potato, or other plants; cellulose such as methyl cellulose,hydroxypropylmethyl-cellulose, or sodium carboxy-methylcellulose; andgums including arabic and tragacanth; and proteins, e.g., gelatin andcollagen. Disintegrating or solubilizing agents may be added, such asthe cross-linked polyvinyl pyrrolidone, agar, alginic acid, or a saltthereof, such as sodium alginate. Push-fit capsules can contain activeagents mixed with a filler or binders such as lactose or starches,lubricants such as talc or magnesium stearate, and, optionally,stabilizers. In soft capsules, the active agents can be dissolved orsuspended in suitable liquids, such as fatty oils, liquid paraffin, orliquid polyethylene glycol with or without stabilizers.

Aqueous suspensions can contain an active agent (e.g., nucleic acidsequences of the invention) in admixture with excipients suitable forthe manufacture of aqueous suspensions, e.g., for aqueous intradermalinjections. Such excipients include a suspending agent, such as sodiumcarboxymethylcellulose, methylcellulose, hydroxypropylmethylcellulose,sodium alginate, polyvinylpyrrolidone, gum tragacanth and gum acacia,and dispersing or wetting agents such as a naturally occurringphosphatide (e.g., lecithin), a condensation product of an alkyleneoxide with a fatty acid (e.g., polyoxyethylene stearate), a condensationproduct of ethylene oxide with a long chain aliphatic alcohol (e.g.,heptadecaethylene oxycetanol), a condensation product of ethylene oxidewith a partial ester derived from a fatty acid and a hexitol (e.g.,polyoxyethylene sorbitol mono-oleate), or a condensation product ofethylene oxide with a partial ester derived from fatty acid and ahexitol anhydride (e.g., polyoxyethylene sorbitan mono-oleate). Theaqueous suspension can also contain one or more preservatives such asethyl or n-propyl p-hydroxybenzoate, one or more coloring agents, one ormore flavoring agents and one or more sweetening agents, such assucrose, aspartame or saccharin. Formulations can be adjusted forosmolarity.

In some embodiments, oil-based pharmaceuticals are used foradministration of nucleic acid sequences of the invention. Oil-basedsuspensions can be formulated by suspending an active agent in avegetable oil, such as arachis oil, olive oil, sesame oil or coconutoil, or in a mineral oil such as liquid paraffin; or a mixture of these.See e.g., U.S. Pat. No. 5,716,928 describing using essential oils oressential oil components for increasing bioavailability and reducinginter- and intra-individual variability of orally administeredhydrophobic pharmaceutical compounds (see also U.S. Pat. No. 5,858,401).The oil suspensions can contain a thickening agent, such as beeswax,hard paraffin or cetyl alcohol. Sweetening agents can be added toprovide a palatable oral preparation, such as glycerol, sorbitol orsucrose. These formulations can be preserved by the addition of anantioxidant such as ascorbic acid. As an example of an injectable oilvehicle, see Minto (1997) J. Pharmacol. Exp. Ther. 281:93-102.

Pharmaceutical formulations can also be in the form of oil-in-wateremulsions. The oily phase can be a vegetable oil or a mineral oil,described above, or a mixture of these. Suitable emulsifying agentsinclude naturally-occurring gums, such as gum acacia and gum tragacanth,naturally occurring phosphatides, such as soybean lecithin, esters orpartial esters derived from fatty acids and hexitol anhydrides, such assorbitan mono-oleate, and condensation products of these partial esterswith ethylene oxide, such as polyoxyethylene sorbitan mono-oleate. Theemulsion can also contain sweetening agents and flavoring agents, as inthe formulation of syrups and elixirs. Such formulations can alsocontain a demulcent, a preservative, or a coloring agent. In alternativeembodiments, these injectable oil-in-water emulsions of the inventioncomprise a paraffin oil, a sorbitan monooleate, an ethoxylated sorbitanmonooleate and/or an ethoxylated sorbitan trioleate.

The pharmaceutical compounds can also be administered by in intranasal,intraocular and intravaginal routes including suppositories,insufflation, powders and aerosol formulations (for examples of steroidinhalants, see e.g., Rohatagi (1995) J. Clin. Pharmacol. 35:1187-1193;Tjwa (1995) Ann. Allergy Asthma Immunol. 75:107-111). Suppositoriesformulations can be prepared by mixing the drug with a suitablenon-irritating excipient which is solid at ordinary temperatures butliquid at body temperatures and will therefore melt in the body torelease the drug. Such materials are cocoa butter and polyethyleneglycols.

In some embodiments, the pharmaceutical compounds can be deliveredtransdermally, by a topical route, formulated as applicator sticks,solutions, suspensions, emulsions, gels, creams, ointments, pastes,jellies, paints, powders, and aerosols.

In some embodiments, the pharmaceutical compounds can also be deliveredas microspheres for slow release in the body. For example, microspherescan be administered via intradermal injection of drug which slowlyrelease subcutaneously; see Rao (1995) J. Biomater Sci. Polym. Ed.7:623-645; as biodegradable and injectable gel formulations, see, e.g.,Gao (1995) Pharm. Res. 12:857-863 (1995); or, as microspheres for oraladministration, see, e.g., Eyles (1997) J. Pharm. Pharmacol. 49:669-674.

In some embodiments, the pharmaceutical compounds can be parenterallyadministered, such as by intravenous (IV) administration oradministration into a body cavity or lumen of an organ. Theseformulations can comprise a solution of active agent dissolved in apharmaceutically acceptable carrier. Acceptable vehicles and solventsthat can be employed are water and Ringer's solution, an isotonic sodiumchloride. In addition, sterile fixed oils can be employed as a solventor suspending medium. For this purpose any bland fixed oil can beemployed including synthetic mono- or diglycerides. In addition, fattyacids such as oleic acid can likewise be used in the preparation ofinjectables. These solutions are sterile and generally free ofundesirable matter. These formulations may be sterilized byconventional, well known sterilization techniques. The formulations maycontain pharmaceutically acceptable auxiliary substances as required toapproximate physiological conditions such as pH adjusting and bufferingagents, toxicity adjusting agents, e.g., sodium acetate, sodiumchloride, potassium chloride, calcium chloride, sodium lactate and thelike. The concentration of active agent in these formulations can varywidely, and will be selected primarily based on fluid volumes,viscosities, body weight, and the like, in accordance with theparticular mode of administration selected and the patient's needs. ForIV administration, the formulation can be a sterile injectablepreparation, such as a sterile injectable aqueous or oleaginoussuspension. This suspension can be formulated using those suitabledispersing or wetting agents and suspending agents. The sterileinjectable preparation can also be a suspension in a nontoxicparenterally-acceptable diluent or solvent, such as a solution of1,3-butanediol. The administration can be by bolus or continuousinfusion (e.g., substantially uninterrupted introduction into a bloodvessel for a specified period of time).

In some embodiments, the pharmaceutical compounds and formulations canbe lyophilized. Stable lyophilized formulations comprising an inhibitorynucleic acid can be made by lyophilizing a solution comprising apharmaceutical of the invention and a bulking agent, e.g., mannitol,trehalose, raffinose, and sucrose or mixtures thereof. A process forpreparing a stable lyophilized formulation can include lyophilizing asolution about 2.5 mg/mL protein, about 15 mg/mL sucrose, about 19 mg/mLNaCl, and a sodium citrate buffer having a pH greater than 5.5 but lessthan 6.5. See, e.g., U.S. 20040028670.

The compositions and formulations can be delivered by the use ofliposomes. By using liposomes, particularly where the liposome surfacecarries ligands specific for target cells, or are otherwisepreferentially directed to a specific organ, one can focus the deliveryof the active agent into target cells in vivo. See, e.g., U.S. Pat. Nos.6,063,400; 6,007,839; Al-Muhammed (1996) J. Microencapsul. 13:293-306;Chonn (1995) Curr. Opin. Biotechnol. 6:698-708; Ostro (1989) Am. J.Hosp. Pharm. 46:1576-1587. As used in the present invention, the term“liposome” means a vesicle composed of amphiphilic lipids arranged in abilayer or bilayers. Liposomes are unilamellar or multilamellar vesiclesthat have a membrane formed from a lipophilic material and an aqueousinterior that contains the composition to be delivered. Cationicliposomes are positively charged liposomes that are believed to interactwith negatively charged DNA molecules to form a stable complex.Liposomes that are pH-sensitive or negatively-charged are believed toentrap DNA rather than complex with it. Both cationic and noncationicliposomes have been used to deliver DNA to cells.

Liposomes can also include “sterically stabilized” liposomes, i.e.,liposomes comprising one or more specialized lipids. When incorporatedinto liposomes, these specialized lipids result in liposomes withenhanced circulation lifetimes relative to liposomes lacking suchspecialized lipids. Examples of sterically stabilized liposomes arethose in which part of the vesicle-forming lipid portion of the liposomecomprises one or more glycolipids or is derivatized with one or morehydrophilic polymers, such as a polyethylene glycol (PEG) moiety.Liposomes and their uses are further described in U.S. Pat. No.6,287,860.

The formulations of the invention can be administered for prophylacticand/or therapeutic treatments. In some embodiments, for therapeuticapplications, compositions are administered to a subject who is need ofreduced triglyceride levels, or who is at risk of or has a disorderdescribed herein, in an amount sufficient to cure, alleviate orpartially arrest the clinical manifestations of the disorder or itscomplications; this can be called a therapeutically effective amount.For example, in some embodiments, pharmaceutical compositions of theinvention are administered in an amount sufficient to decrease serumlevels of triglycerides in the subject.

The amount of pharmaceutical composition adequate to accomplish this isa therapeutically effective dose. The dosage schedule and amountseffective for this use, i.e., the dosing regimen, will depend upon avariety of factors, including the stage of the disease or condition, theseverity of the disease or condition, the general state of the patient'shealth, the patient's physical status, age and the like. In calculatingthe dosage regimen for a patient, the mode of administration also istaken into consideration.

The dosage regimen also takes into consideration pharmacokineticsparameters well known in the art, i.e., the active agents' rate ofabsorption, bioavailability, metabolism, clearance, and the like (see,e.g., Hidalgo-Aragones (1996) J. Steroid Biochem. Mol. Biol. 58:611-617;Groning (1996) Pharmazie 51:337-341; Fotherby (1996) Contraception54:59-69; Johnson (1995) J. Pharm. Sci. 84:1144-1146; Rohatagi (1995)Pharmazie 50:610-613; Brophy (1983) Eur. J. Clin. Pharmacol. 24:103-108;Remington: The Science and Practice of Pharmacy, 21st ed., 2005). Thestate of the art allows the clinician to determine the dosage regimenfor each individual patient, active agent and disease or conditiontreated. Guidelines provided for similar compositions used aspharmaceuticals can be used as guidance to determine the dosageregiment, i.e., dose schedule and dosage levels, administered practicingthe methods of the invention are correct and appropriate.

Single or multiple administrations of formulations can be givendepending on for example: the dosage and frequency as required andtolerated by the patient, the degree and amount of therapeutic effectgenerated after each administration (e.g., effect on tumor size orgrowth), and the like. The formulations should provide a sufficientquantity of active agent to effectively treat, prevent or ameliorateconditions, diseases or symptoms.

In alternative embodiments, pharmaceutical formulations for oraladministration are in a daily amount of between about 1 to 100 or moremg per kilogram of body weight per day. Lower dosages can be used, incontrast to administration orally, into the blood stream, into a bodycavity or into a lumen of an organ. Substantially higher dosages can beused in topical or oral administration or administering by powders,spray or inhalation. Actual methods for preparing parenterally ornon-parenterally administrable formulations will be known or apparent tothose skilled in the art and are described in more detail in suchpublications as Remington: The Science and Practice of Pharmacy, 21sted., 2005.

Various studies have reported successful mammalian dosing usingcomplementary nucleic acid sequences. For example, Esau C., et al.,(2006) Cell Metabolism, 3(2):87-98 reported dosing of normal mice withintraperitoneal doses of miR-122 antisense oligonucleotide ranging from12.5 to 75 mg/kg twice weekly for 4 weeks. The mice appeared healthy andnormal at the end of treatment, with no loss of body weight or reducedfood intake. Plasma transaminase levels were in the normal range (AST ¾45, ALT ¾ 35) for all doses with the exception of the 75 mg/kg dose ofmiR-122 ASO, which showed a very mild increase in ALT and AST levels.They concluded that 50 mg/kg was an effective, non-toxic dose. Anotherstudy by Krutzfeldt J., et al., (2005) Nature 438, 685-689, injectedanatgomirs to silence miR-122 in mice using a total dose of 80, 160 or240 mg per kg body weight. The highest dose resulted in a complete lossof miR-122 signal. In yet another study, locked nucleic acids (“LNAs”)were successfully applied in primates to silence miR-122. Elmen J., etal., (2008) Nature 452, 896-899, report that efficient silencing ofmiR-122 was achieved in primates by three doses of 10 mg kg-1LNA-antimiR, leading to a long-lasting and reversible decrease in totalplasma cholesterol without any evidence for LNA-associated toxicities orhistopathological changes in the study animals.

In some embodiments, the methods described herein can includeco-administration with other drugs or pharmaceuticals, e.g.,compositions for providing cholesterol homeostasis. For example, theinhibitory nucleic acids can be co-administered with drugs for treatingor reducing risk of a disorder described herein.

Methods of Screening Test Compounds

Included herein are methods for screening test compounds, e.g.,polypeptides, polynucleotides, inorganic or organic large or smallmolecule test compounds, to identify agents useful in the treatment ofdisorders associated with memory dysfunction or anxiety as describedherein.

As used herein, “small molecules” refers to small organic or inorganicmolecules of molecular weight below about 3,000 Daltons. In general,small molecules useful for the invention have a molecular weight of lessthan 3,000 Daltons (Da). The small molecules can be, e.g., from at leastabout 100 Da to about 3,000 Da (e.g., between about 100 to about 3,000Da, about 100 to about 2500 Da, about 100 to about 2,000 Da, about 100to about 1,750 Da, about 100 to about 1,500 Da, about 100 to about 1,250Da, about 100 to about 1,000 Da, about 100 to about 750 Da, about 100 toabout 500 Da, about 200 to about 1500, about 500 to about 1000, about300 to about 1000 Da, or about 100 to about 250 Da).

The test compounds can be, e.g., natural products or members of acombinatorial chemistry library. A set of diverse molecules should beused to cover a variety of functions such as charge, aromaticity,hydrogen bonding, flexibility, size, length of side chain,hydrophobicity, and rigidity. Combinatorial techniques suitable forsynthesizing small molecules are known in the art, e.g., as exemplifiedby Obrecht and Villalgordo, Solid-Supported Combinatorial and ParallelSynthesis of Small-Molecular-Weight Compound Libraries,Pergamon-Elsevier Science Limited (1998), and include those such as the“split and pool” or “parallel” synthesis techniques, solid-phase andsolution-phase techniques, and encoding techniques (see, for example,Czarnik, Curr. Opin. Chem. Bio. 1:60-6 (1997)). In addition, a number ofsmall molecule libraries are commercially available. A number ofsuitable small molecule test compounds are listed in U.S. Pat. No.6,503,713, incorporated herein by reference in its entirety.

Libraries screened using the methods of the present invention cancomprise a variety of types of test compounds. A given library cancomprise a set of structurally related or unrelated test compounds. Insome embodiments, the test compounds are peptide or peptidomimeticmolecules. In some embodiments, the test compounds are nucleic acids.

In some embodiments, the test compounds and libraries thereof can beobtained by systematically altering the structure of a first testcompound, e.g., a first test compound that is structurally similar to aknown natural binding partner of the target polypeptide, or a firstsmall molecule identified as capable of binding the target polypeptide,e.g., using methods known in the art or the methods described herein,and correlating that structure to a resulting biological activity, e.g.,a structure-activity relationship study. As one of skill in the art willappreciate, there are a variety of standard methods for creating such astructure-activity relationship. Thus, in some instances, the work maybe largely empirical, and in others, the three-dimensional structure ofan endogenous polypeptide or portion thereof can be used as a startingpoint for the rational design of a small molecule compound or compounds.For example, in one embodiment, a general library of small molecules isscreened, e.g., using the methods described herein.

In some embodiments, the screen includes a cell-based assay as describedherein, e.g., an assay for small molecule disruptors of ablim3localization at adherens junctions as described in Example 2. Forexample, a test compound is applied to a test sample, e.g., a populationof cells that express Ablim3, e.g., an Ablim3 reporter construct inwhich Ablim3 is linked in frame to a detectable label (e.g., afluorescent protein), and one or more effects of the test compound isevaluated. For example, localization of Ablim3 to adherens junctions canbe evaluated; molecules that disrupt Ablim3 localization to adherensjunctions, but not actin stress fibers, are candidates for inhibitingablim3 in vivo. A number of detectable labels are known in the art,including but not limited to, various enzymes, prosthetic groups,fluorescent materials, luminescent materials, chromogenic materials,bioluminescent materials, and radioactive materials. Examples ofsuitable enzymes include horseradish peroxidase, alkaline phosphatase,β-galactosidase, or acetylcholinesterase; examples of suitableprosthetic group complexes include streptavidin/biotin andavidin/biotin; examples of suitable fluorescent materials includeumbelliferone, fluorescein, fluorescein isothiocyanate, rhodamine,dichlorotriazinylamine fluorescein, dansyl chloride, quantum dots, orphycoerythrin; an example of a luminescent material includes luminol;examples of bioluminescent materials include luciferase, luciferin, andaequorin, and examples of suitable radioactive material include ¹²⁵I,¹³¹I, ³⁵S, or ³H. Other labels include colored particles such ascolloidal gold or latex beads.

A cilia screen can be used to further validate candidate molecules. Forexample, shRNAs against ablim3 can be used to assess specificity of thesmall molecule candidates. If disrupting ablim3-PAJ association confersa loss of function phenotype, then small molecule treatment of ciliatedcells that express ablim3 shRNA should not augment cilia number orlength.

In some embodiments, the test sample is, or is derived from (e.g., asample taken from) a patient or an in vivo model of a disorder asdescribed herein. For example, cells from a human patient or an animalmodel, e.g., a rodent such as a rat, can be used.

A test compound that has been screened by a method described herein anddetermined to disrupt ablim3-PAJ association can be considered acandidate compound. A candidate compound that has been screened, e.g.,in an in vivo model of a disorder, e.g., a rodent model as describedherein, and determined to have a desirable effect on the disorder, e.g.,on one or more symptoms of the disorder (e.g., on memory), can beconsidered a candidate therapeutic agent. Candidate therapeutic agents,once screened in a clinical setting, are therapeutic agents. Candidatecompounds, candidate therapeutic agents, and therapeutic agents can beoptionally optimized and/or derivatized, and formulated withphysiologically acceptable excipients to form pharmaceuticalcompositions.

In addition, test compounds identified as “hits” (e.g., test compoundsthat disrupt ablim3-PAJ association, or that improve memory in an animalmodel) can be selected and systematically altered, e.g., using rationaldesign, to optimize binding affinity, avidity, specificity, or otherparameter. Such optimization can also be screened for using the methodsdescribed herein. Thus, in one embodiment, the invention includesscreening a first library of compounds using a method known in the artand/or described herein, identifying one or more hits in that library,subjecting those hits to systematic structural alteration to create asecond library of compounds structurally related to the hit, andscreening the second library using the methods described herein.

Test compounds identified as hits can be considered candidatetherapeutic compounds, useful in treating disorders associated withmemory dysfunction as described herein. A variety of techniques usefulfor determining the structures of “hits” can be used in the methodsdescribed herein, e.g., NMR, mass spectrometry, gas chromatographyequipped with electron capture detectors, fluorescence and absorptionspectroscopy. Thus, the invention also includes compounds identified as“hits” by the methods described herein, and methods for theiradministration and use in the treatment, prevention, or delay ofdevelopment or progression of a disorder described herein.

Test compounds identified as candidate therapeutic compounds can befurther screened by administration to an experimental animal, e.g., ananimal model of a disorder associated with memory loss, as describedherein. The animal can be monitored for a change in the disorder, e.g.,for an improvement in a parameter of the disorder, e.g., a parameterrelated to clinical outcome. In some embodiments, the parameter ismemory loss, and an improvement would be improved memory. In someembodiments, the subject is a human, e.g., a human with AD, and theparameter is improvement in memory, decreased frequency of memorylapses, or delayed or slowed progression of memory loss of demetia. Insome embodiments, the subject is a human, e.g., a human with an anxietydisorder, and the parameter is improvement in anxiety, or decreasedfrequency or severity of anxiety episodes or panic attacks, or adecreased association of anxiety-inducing stimuli with anxiety attacks.

EXAMPLES

The invention is further described in the following examples, which donot limit the scope of the invention described in the claims.

Example 1

The following materials and methods were used in this Example

Data analysis and statistics. Statistical analysis will be carried outusing StatView software and statistical significance will be assessed byunpaired two-tailed student's t-tests or ANOVA. Significant main effectsor interactions were followed up with Fisher's predicted least-squaredifference post hoc tests where appropriate. Behavioral phenotypedifferences will be considered significant if an unpaired t-test betweenthe control condition and test groups or ANOVA gives a p-value below0.05.

Characterization of shRNAs for Ablim3. Commercially available candidateshRNAs (Dharmacon, 5′-AAACCCAGGGCTGCCTTGGAAAAG-3′; SEQ ID NO:1) werescreened for ablim3 knockdown efficiency in vitro using a HA-taggedcoding sequence of ablim3 that was cloned into the retroviral vector pUX(kindly provided by Dr. Ge, Stony Brook University). shRNA-mediatedknockdown efficiency was assessed by co-transfecting expression vectorfor Ablim3-pUX and shRNAs into 293T cells and using HA-tagged GFP astransfection control. Cells were lysed and subjected to western blot forAblim3 expression using anti-Ablim3 or anti-GFP (Abcam) antibodies.

Virus generation and in vivo stereotaxic injections. Candidate shRNAsequences and non-targeted shRNA sequence were cloned into theretroviral vector pUEG (kindly provided by Dr. Ge). Engineeredretroviruses were produced by co-transfection of shRNA-pUEG vectors andVSVG into HEK293gp cells. Virus-containing supernatant was harvested 36,48 and 60 hours after transfection and concentrated byultracentrifugation at 25,000 rpm for 1.5 hours as we recently published(Ikrar et al., 2013). For the lentiviral constructs, shRNAs sequenceswere cloned into the HapI and XhoI sites of the lentiviral vector pLLX,which contain a GFP protein driven by ubiquitin promoter. Thelenti-ablim3IRES GFP construct was made using a LEMPRA backbone (Zhou etal., 2006). Low titre engineered lentiviruses were produced byco-transfection of shRNA-pLLX vectors, VSVG and Δ8.9 into HEK293T cellsfollowed by ultracentrifugation of viral supernatant at 20,000 rpm for 2hr. Adult and aged C57BL/6 mice were maintained under standardconditions and viruses were stereotaxically injected into the DG at 2sites (0.5 μl per site at 0.1 μl/min) with the following coordinates:anterioposterior=−2 mm from bregma; lateral=±1.6 mm; ventral=2.5 mm aswe recently published (Ikrar et al., 2013). Injection needles were leftin place additional 10 minutes after injection to ensure evendistribution of the virus. For behavioral analysis, we will scale upvirus production to generate high titre viruses. Adult and aged C57BL/6female mice were obtained from National Institute on Aging.

Confocal analysis of MFT, MFT-filopodia and dendritic spines. Forquantification of MFTs and MFT-filopodial contacts with PV+ interneuronsconfocal z-stack images were acquired using a Nikon AlR Si confocallaser, a TiE inverted research microscope, and NIS Elements software(Nikon Instruments, 1300 Walt Whitman Road, Melville, N.Y. 11747-3064)as we recently published (Ikrar et al., 2013). Images of CA3ab weretaken using a 60× objective at a resolution of 1024×1024 pixels (0.31μm/px) with pixel dwell time set at 0.5 μm/s and line averaging at 2.Three-dimensional Z-series stacks were captured at 0.5 μm incrementswith six to eight times optical zoom. For spine imaging, confocal 2.1 uMz-stacks (2048 resolution) with 0.3 uM step size were taken centered ondendritic segment. Imaging was performed using a 60× objective, plus1.5× optical zoom and 6× digital zoom, using 2× frame averaging at eachstep to eliminate background. Z-stack were flattened using the maximumintensity projection, and flattened images were quantified using imageJ. For spine density, spines per measured dendritic length were countedmanually, and head diameter (widest point) and length (furthest pointfrom dendrite) were taken for individual spines to calculate spine sizedistribution.

catFISH. c-fos cRNA probe was used to assess localization of cytoplasmicRNAs. Nuclear localization was assessed using intronic c-fos probe(kindly provided by Dr. Dayu Lin, NYU) and protocol previously reported(Lin et al., 2011). To assess % non-overlap of activated cells in eachcontext, z-stacks of dorsal CA3ab neurons will be captured and we willquantify the number of CA3 pyramidal neurons that show nuclear,cytoplasmic or nuclear+cytolasmice c-fos following exposure to thesecond environment using NIH Image J software.

Immunohistochemistry and ISH. Immunohistochemistry for c-fos, Ablim3,VGLUT1, PV and Z0-1 was performed using protocols reported previously(Ruediger et al., 2011). ISH for ablim3 was done as we have previouslyreported (Scobie et al., 2009). We quantified c-fos signal intensitiesfrom cells in dorsal CA3 in 4 matched sections per mouse. High (abovemean) and low (below mean) c-fos signal was based on the mean ofpopulation quantified in each section following background subtraction(signal in stratum radiatum). All sections and images used forcomparisons were processed in the same experiment and acquired withidentical settings, respectively.

Contextual fear discrimination. Contextual fear conditioning wasperformed using 4 chambers Coulburn apparatus. The protocol entaileddelivery of 2 1-second foot shocks of 0.75 mA spaced apart by 60 secondsand 180 seconds following placement in training context. The mouse wastaken out 60 seconds following second foot shock and returned to itshome cage. No differences in acquisition were seen between aged andadult mice. On testing days, mice were brought out of the vivarium andallowed to habituate for an hour outside the testing room prior tostarting the experiment. Mouse behaviour was recorded by digital videocameras mounted above conditioning chambers. The chamber was lit fromabove with a houselight (CM1820 bulb), ventilated with a house fan andencased by a sound-dampening cubicle. Freezeframe and Freezeviewsoftware (Actimetrics, Evanston, Ill.) were used for recording andanalyzing freezing behaviour, respectively. For shock associatedtraining context A, the house fan and lights were switched on andstainless steel grids were exposed. 70% ethanol was used to clean gridsin between runs. The similar context B had cardboard covering the wallsand the grids. The house fan and lights were switched off and the doorwas left ajar for providing lighting for the camera. Grid-floors werecleaned with tissue without ethanol. Both contexts A and B were housedin Coulburn chambers. Context C was outside the chamber but housed inthe same room as the chambers. It is comprised of a paper bucket in aplastic box. Mice were brought into testing room in a red plasticcontainer.

Example 1.1 Increasing FFE Connectivity of Adult-Born dg Neurons inAdult Mice is Sufficient to Produce Aging Related Alterations in CA3 andEncoding and Memory Imprecision

Analysis of FFE and FFI connectivity during aging revealed an increasein MFT size and decreased number of VGLUT1+ve MFT-filopodial contacts ofmature dg neurons with SL PV+ve interneurons (FIG. 1A-B) in aged micerelative to adult mice. At a behavioral level, aged mice showed impaireddiscrimination of two similar, but not distinct, contexts compared toadult or middle-aged mice (FIG. 2A-C). Since increased freezing in thesimilar context (context B) may arise due to excessive patterncompletion in CA3, we examined activation of CA3 in adult and aged miceand learning dependent changes in FFI connectivity following exposure tothe similar context B. Aged mice showed fewer “high” c-fos expressingcells and more “low” c-fos expressing cells in CA3 compared with adultmice (FIG. 2D). These changes were paralleled by a failure to showrobust learning dependent enhancement of FFI connectivity (VGLUT1+veMFT-filopodial contacts of mature dg neurons with SL PV+ve interneurons)as seen in adult mice (FIG. 2E-F). Interestingly, the same constellationof changes (elevated numbers of low cfos+ cells and decreased number ofhigh c-fos+ cells in CA3 and decreased FFI connectivity) are seen inmice that show impaired contextual memory precision and increasedgeneralization of contextual fear (Ruediger et al., 2011). Furthermore,these observations are reminiscent of elevated CA3 place cell firing inaged rodents (Wilson et al., 2005) and humans (Bakker et al., 2012)during retrieval. Together, these observations suggest that decreasedFFI or increased FFE-FFI ratio in aging results in over activation ofCA3 during retrieval thereby impeding memory precision and patternseparation-completion balance.

Levels of adult hippocampal neurogenesis are also dramatically reducedwith aging (FIG. 1C). Adult-born dg neurons are both necessary andsufficient for pattern separation involving discrimination of similarfearful and safe contexts (Tronel et al., 2010; Sahay et al., 2011;Nakashiba et al., 2012; Niibori et al., 2012) through global remappingin CA3 (Niibori et al., 2012). Interestingly, young adult-born dgneurons exhibit highest number of MFT-filopodia (corresponding todecreased FFE FFI ratio) at a stage (4 weeks) when they show heightenedsynaptic plasticity (Snyder et al., 2001; Schmidt-Hieber et al., 2004;Saxe et al., 2006; Ge et al., 2007; Massa et al., 2011) and that thereis a progressive reduction in MFT-filopodial number coupled with growthin MFT size, suggestive of decreasing FFI and increasing FFE(corresponding to increasing FFE-FFI ratio), during maturation ofadult-born dg neurons (FIG. 4A). One mechanism by which interferencebetween similar inputs is minimized and constrains excessive patterncompletion in CA3 is pattern separation through global remapping in CA3,a neural mechanism by which similar environments are encoded byindependent or non-overlapping neuronal-ensembles in CA3 (FIG. 1A).Interestingly, adult-born neurons have been shown to be required forglobal remapping CA3 (Niibori et al., 2012) and aged mice show impairedglobal remapping in CA3 (Wilson et al., 2005).

To identify molecular regulators of MFT-filopodial plasticity, weperformed a screen for targets of a transcription factor, Kruppel-likefactor 9 (Klf9), in the DG, which we found to be upregulated asadult-born dg neurons integrate into DG-CA3 circuitry (Scobie et al.,2009). We hypothesized that some Klf9-target genes are likely to play arole in shaping connectivity of adult-born dg neurons. We examinedexpression patterns of candidate targets by in situ hybridization (ISH)and identified ablim3, a F-Actin binding protein, whose transcripts arehighly enriched in dg neurons but not in hilar cell types and are foundat low levels in CA1. Interestingly, Ablim3 is exclusively localized toMFT-CA3 spine contact sites known as puncta adherens junctions (PAJs)within MFTs, and is absent from other hippocampal molecular layers andelsewhere in adult forebrain (FIG. 3A-C). Because PAJs play a role instructural plasticity and Ablim3 associates with F-actin (Matsuda etal., 2010), we surmised that Ablim3 acts as a brake on MFT structuralplasticity with increasing Ablim3 levels stabilizing the MFT anddecreasing Ablim3 levels facilitating MFT remodeling and increasingMFT-filopodial number (FIG. 3E). Consistent with this proposal,retroviral overexpression of Ablim3 in adult-born dg neurons increasedMFT size (FIG. 4B) and aged mice showed increased levels of Ablim3expression following training compared with adult mice (FIG. 3D). Thesedata suggest that Ablim3 may be molecularly harnessed to increase FFEconnectivity in dg neurons.

Based on these observations and the emerging evidence for FFI inencoding and memory precision (Ruediger et al., 2011; Ruediger et al.,2012), but without wishing to be bound by theory, it was hypothesizedthat increased FFE (and increased FFE-FFI ratio) causally underliesalterations in CA3 properties and encoding and memory imprecision inaging. Since a lack of young adult-born dg neurons (contributors of highFFI) as well as increased FFE and decreased FFI of mature dg neuronscontributes to the increased FFE-FFI ratio in DG-CA3 circuit in aging,we tested whether increasing FFE connectivity by overexpression ofAblim3 in just young adult-born dg neurons in adulthood is sufficient toproduce age-related alterations in CA3 properties and encoding andmemory imprecision.

Example 1.2 Increasing FFI Connectivity of Mature dg Neurons in AgedMice is Sufficient to Reverse Aging Related Alterations in CA3 andEncoding and Memory Imprecision

We have identified changes in connectivity underlying FFE and FFI inaged mice that we hypothesize causally contributes to hyperactivation ofCA3 during retrieval, impaired global remapping in CA3 and impaireddiscrimination of similar contexts. Specifically, we found that maturedg neurons show increased MFT size, a profound reduction inMFT-filopodial contacts with SL PV+ interneurons and impaired learninginduced enhancement in FFI (FIG. 1A-B, FIG. 2E-F). Furthermore, youngadult-born dg neurons, which are indispensable for pattern separation(Tronel et al., 2010; Sahay et al., 2011; Nakashiba et al., 2012;Niibori et al., 2012) through global remapping in CA3 (Niibori et al.,2012) exhibit highest FFI connectivity (FIG. 4A). Since aged mice shownegligible levels of adult hippocampal neurogenesis (FIG. 1C),reengineering FFI connectivity of mature dg neurons to young adult-borndg neuron-like state may restore E-I and pattern separation-completionbalance and reverse CA3 hyperactivation during retrieval.

Based on our model for Ablim3 functions in MFT remodeling duringlearning (FIG. 3E), we interrogated the impact of selectivedownregulation of Ablim3 in mature dg neurons in adult (2 months) andaged (16 months) mice.

Using lentivirally expressed shRNAs that downregulate Ablim3 levels(FIG. 5A), we found that we can dramatically increase the number ofVGLUT1+MFT-filopodial contacts of mature dg neurons with SL PV+interneurons in both adult and aged mice without affecting dg neuronaldendritic spine density (FIG. 5B-D). These results suggest thatdownregulating Ablim3 levels in mature dg neurons of aged mice canreverse aging related alterations in CA3 and encoding and memoryimprecision.

To determine if Ablim3 acts as a brake on MFT filopodial plasticity inmature dg neurons in vivo, we engineered lentiviruses to express GFP andshRNA #46 or a NT shRNA (FIG. 5A-B). We injected viruses expressingthese shRNAs into the dorsal DG of adult (3 months old) or aged (16months old) female C57BL/6 mice and performed confocal microscopy toexamine the MFT and MFT-filopodia at 2 weeks p.i. Downregulation of

Ablim3 significantly increased the number of VGLUT1+MFT-filopodialcontacts with SL PV+ interneurons in CA3ab and did not affect dendriticspine density (FIG. 5B-D). Importantly, Ablim3 downregulation restoredthe number of VGLUT1+MFT-filopodial contacts of mature dg neurons withSL PV+ interneurons to levels seen in 4 weeks old adult-born dg neurons(FIG. 4A). That two different shRNAs (nos. 46 and 47, data not shown)produced identical phenotypes using lentiviruses argues against thecontribution of off-target effects of shRNA to the observed phenotypes.In a separate series of experiments, we used a retroviral expressionsystem to downregulate Ablim3 just in adult-born dg neurons. As isevident in FIG. 5E, downregulation of Ablim3 in adult-born dg neuronsproduced long-lasting, persistent enhancement in number ofMFT-filopodia. Since ablim3 expression is restricted to dg neurons in DGand is absent from mossy cell and hilar interneurons, we expect ourmanipulation to specifically enhance FFI connectivity of mature dgneurons without changing input specificity or properties of otherneuronal cell types in DG.

Example 2 Identifying Small Molecule Negative Regulators of Ablim3Function Using a Cell-Based Assay for Ablim3 Localization

The generation of small molecule regulators of Ablim3 will enablepharmacological modulation of pattern separation in the diseased brain.Without wishing to be bound by theory, it is hypothesized that thelocalization of ablim3 to the PAJ is critical for its regulation of MFfilopodia and synaptic remodeling. Therefore, disrupting ablim3localization should mimic ablim3 loss of function and increase MFfilopodial plasticity.

Heterologous GFP-ablim3 expression in NIH3T3 fibroblasts confines ablim3to adherens junctions at sites of cell-cell contact (Matsuda et al.,2010). A stable NIH3T3 fibroblasts cell line that over expressesGFP-ablim3 is generated (FIG. 6A). The NINDs custom collection 2 libraryof characterized bioactive compounds is used to screen for smallmolecule disruptors of ablim3 localization at adherens junctions. Thisis done by analyzing GFP-ablim3 at the adherens junctions (light greycrossed lines ‘x’ in top left panel of FIG. 6B) following processingwells of compound-treated cells with antibodies against GFP and ZO1(dark grey crossed lines ‘x’ in top right panel of FIG. 6B). This screenmay be made high throughput by automating the quantification. Putativecandidates that also disrupt the actin cytoskeleton are eliminated sincethis will affect ablim3 localization. All compounds are tested intriplicate and at different doses to generate dose response curves.

The function of ablim3 in MF filopodial plasticity and ciliogenesisappears to be remarkably conserved, i.e. down regulation of ablim3 in aciliated cell line increases the number and length of cilia (Cao et al.,2012). Repression of branched F-actin (necessary for lamellopodia) isthought to facilitate ciliogenesis (Cao et al., 2012) and act downstreamto the endocytic recycling pathway (Kim et al., 2010). Since ablim3represses branched F-actin (hence the smaller MFTs, FIG. 3C (Cao et al.,2012)), whether candidate compounds identified in the localizationscreen increase cilia length and number without affecting vesiclerecycling is ascertained. A ciliated cell line is used in which cilia isgenetically labeled with red fluorescent protein, RFP, (Ivs:Tag RFPT)that also expresses GFP tagged Smoothened receptor (GFP-Smo) developedby Andy McMahon, Lee Rubin and colleagues (Wang et al., 2012). TheSmo-GFP allows assessment of effects on the endocytic vesicle pathway.An automated screening protocol as done by Lee Rubin and colleagues(Wang et al., 2012) is used to assess changes in cilia length and numberand alterations in Smo-GFP localization.

For target validation, shRNAs against ablim3 are used to assessspecificity of the small molecule candidates. If disrupting ablim3-PAJassociation confers a loss of function phenotype, then small moleculetreatment of ciliated cells that express ablim3 shRNA should not augmentcilia number or length.

Molecules that disrupt GFP-ablim3 localization to adherens junctions,but not actin stress fibers, are candidates for inhibiting ablim3 invivo. The cilia screen will further validate candidate molecules.

Example 3 Assess Procognitive Potential of Small Molecule Regulators ofAblim3 in Aged Mice

Small molecules that disrupt ablim3 localization to adherens junctionsin vitro are likely to inhibit ablim3 localization to PAJs in vivo.Here, without wishing to be bound by theory, it is hypothesized thatsmall molecule inhibitors of ablim3 localization to PAJs will producethe same phenotypes as ablim3 downregulation, i.e. increased filopodianumber and length and enhance pattern separation.

The dose necessary to enhance MF filopodia in vivo is determined. Acandidate small molecule is administered intraperitoneally at differentdoses to genetic reporter mice (Thy-1 M GFP) that allow us to visualizeMF filopodia. Once the dose is established, the behavioral impact ofsmall molecule enhancement of MF filopodia is assessed. In contrast toviral manipulations which are sustained due to viral integration in thegenome, small molecules will afford temporal control of MF filopodialplasticity. Since aged mice show impaired pattern separation (Creer etal., 2010), whether pattern separation impairments in aged mice can bereversed is assessed using behavioral paradigms described above.

Example 4 FFE-FFI Balance Mediated by Adult-Born dg Neurons is Necessaryfor Pattern Separation of Contexts and Predictors of Contingency byGlobal Remapping

Adult-born dg neurons have been found to be both necessary andsufficient for pattern separation involving discrimination of similarfearful and safe contexts (Tronel et al., 2010; Sahay et al., 2011b;Nakashiba et al., 2012; Niibori et al., 2012) through global remappingin CA3 (Niibori et al., 2012). However, the mechanisms by whichadult-born dg neurons contribute to pattern separation are poorlyunderstood. Without wishing to be bound by theory, the present inventorspropose a role for E-I balance in mediating the effects of adult-bornneurons on pattern separation. Furthermore, it is proposed thatadult-born dg neuron dependent pattern separation also underliediscrimination of cues that predict contingency through global remappingin CA3. The basis for this proposal is as follows: 1. The hippocampushas been shown to participate in encoding uncertainty of cue-contingencyassociations in humans (Vanni-Mercier et al., 2009). 2. Silencing the DGin an “anxious” serotonin mouse mutant ameliorates discrimination ofpredictors of contingency, whereas impaired discrimination of predictorsof contingency is associated with increased activation of the DG(Tsetsenis et al., 2007; Enkel et al., 2010). 3. Sparseness ofactivation in DG, a property important for pattern separation by globalremapping, may be modulated by adult hippocampal neurogenesis (Sahay etal., 2011a; Piatti et al., 2013). 4. Global remapping in DG is seen whendifferent search strategies within the same spatial maze are usedsuggesting that it may be a general mechanism to minimize interference,independent of modality and spatial cue processing (Satvat et al.,2011). The wiring diagram of the DG-CA3 circuit shows exquisiteanatomical segregation of FFE and FFI within the MFT (Acsady et al.,1998; McBain, 2008). Specifically, dg neurons make excitatoryconnections with CA3 neurons via large NIFTs and onto parvalbumin (PV)+ve inhibitory interneurons in stratum lucidum via vesicular glutamatetransporter-1 (VGLUT1) +ve filopodia emanating from the NIFTs (FIG. 1A).Since these interneurons inhibit CA3 neurons, the synaptic connectionsof MFT filopodia and MFTs influence excitation-inhibition balance, aproperty thought to be important for sparse encoding in the DG-CA3circuit (O'Reilly and McClelland, 1994; Rolls, 1996; Mori et al., 2007;Treves et al., 2008; Ferrante et al., 2009; Ruediger et al., 2011;Ruediger et al., 2012; Piatti et al., 2013). Moreover, MFT filopodiaexhibit plasticity in response to learning and MFT filopodia numbercorrelate very tightly with memory precision (Ruediger et al., 2011;Ruediger et al., 2012).

Green fluorescent protein (GFP)-expressing retroviruses were used togenetically label adult-born dg neurons at distinct stages of maturation(14, 28 and 56 dpi) in C57BL/6J mice and MFT size and MFT filopodia wereanalyzed by confocal microscopy (FIG. 1A, 7A). Mature dg neurons wereinfected with lentivirus expressing GFP and two weeks later MFTfilopodia were analyzed following a contextual fear discrimination taskpreviously shown to require pattern separation and global remapping inCA3 (Sahay et al., 2011b; Nakashiba et al., 2012; Niibori et al., 2012;Deng et al., 2013) (FIG. 7B) as follows. Briefly, mice had todistinguish a context in which they received a foot shock (context A)from a similar safe context “B”. The mice were also tested in acompletely different context “C” to ascertain if an observeddiscrimination phenotype is restricted to conditions with high contextsimilarity indicative of a pattern separation-impairment and not anotherencoding function (Niibori et al., 2012; Deng et al., 2013). Mice wereanalyzed on day 3 following exposure to just context B.

We found that adult-born dg neurons exhibit highest number of MFTfilopodia (decreased FFE-FFI ratio) at a stage (4 weeks) when they showheightened synaptic plasticity (Snyder et al., 2001; Schmidt-Hieber etal., 2004; Saxe et al., 2006; Ge et al., 2007; Massa et al., 2011) andthat there is a progressive restriction in filopodia) number coupledwith growth in MFT size, suggestive of decreasing FFI and increasing FFE(increasing FFE-FFI ratio), during maturation of adult-born dg neurons(FIG. 7A). Furthermore, MFT filopodia number in mature dg neurons isincreased following discrimination of similar contexts, a task thoughtto require pattern separation (Sahay et al., 2011b; Nakashiba et al.,2012; Niibori et al., 2012; Deng et al., 2013) (FIG. 7B). Thus,modulation of MFT filopodia) plasticity and MFT size of adult-bornneurons may dictate FFI-FFE balance in DG-CA3 and consequently, patternseparation.

As described above, Ablim3 was identified in a screen for targets ofKlf9; Ablim3 is exclusively localized to MFT-CA3 spine contact sitesknown as puncta adherens junctions (PAJs) within MFTs, and is absentfrom other hippocampal molecular layers and elsewhere in adultforebrain. The localization of Ablim3 suggests that it may act as abrake on structural plasticity and its downregulation facilitatessynapse remodeling and MFT plasticity (FIG. 3A-D). Retroviral regulationof Ablim3 levels in adult-born neurons (FIG. 4) diametrically regulatesFFE and FFI and since small MFTs that innervate hilar interneurons donot have PAJs, Ablim3 may be harnessed to selectively modulate FFE-FFIbalance (without affecting feedback inhibition onto the DG) inadult-born neurons.

Furthermore, Ablim3 down regulation in dg neurons of aged mice wassufficient to enhance long-term contextual fear memory, activation of PVinterneurons, number of c-fos (high) in CA3 neurons without affecting DGactivation. Downregulation of Ablim3 using virally-administered shRNAcausally increased PV+ activation, number of c-fos (high) cells in CA3and long-term contextual fear memory. Consistent with Ablim3 absent inmossy cell and hilar interneurons, DG activation was unchanged andfeed-back inhibition was maintained (FIGS. 8A-C).

REFERENCES

Acsady L, Kali S (2007) Models, structure, function: the transformationof cortical signals in the dentate gyms. Prog Brain Res 163:577-599.

Acsady L, Kamondi A, Sik A, Freund T, Buzsaki G (1998) GABAergic cellsare the major postsynaptic targets of mossy fibers in the rathippocampus. J Neurosci 18:3386-3403.

Bakker A, Kirwan C B, Miller M, Stark C E (2008) Pattern separation inthe human hippocampal CA3 and dentate gyms. Science 319:1640-1642.

Bakker A, Krauss G L, Albert M S, Speck C L, Jones L R, Stark C E, YassaM A, Bassett S S, Shelton A L, Gallagher M (2012) Reduction ofhippocampal hyperactivity improves cognition in amnestic mild cognitiveimpairment. Neuron 74:467-474.

Barnes C A, McNaughton B L (1980) Physiological compensation for loss ofafferent synapses in rat hippocampal granule cells during senescence.The Journal of physiology 309:473-485.

Biedenkapp J C, Rudy J W (2007) Context preexposure prevents forgettingof a contextual fear memory: implication for regional changes in brainactivation patterns associated with recent and remote memory tests.Learning & memory (Cold Spring Harbor, N.Y. 14:200-203.

Blanchard R J, Hebert M A, Ferrari P F, Palanza P, Figueira R, BlanchardD C, Parmigiani S (1998) Defensive behaviors in wild and laboratory(Swiss) mice: the mouse defense test battery. Physiol Behav 65:201-209.

Boldrini M, Hen R, Underwood M D, Rosoklija G B, Dwork A J, Mann J J,Arango V (2012) Hippocampal angiogenesis and progenitor cellproliferation are increased with antidepressant use in major depression.Biol Psychiatry 72:562-571.

Boldrini M, Underwood M D, Hen R, Rosoklija G B, Dwork A J, John Mann J,Arango V (2009) Antidepressants increase neural progenitor cells in thehuman hippocampus. Neuropsychopharmacology 34:2376-2389.

Bragin A, Jando G, Nadasdy Z, van Landeghem M, Buzsaki G (1995) DentateEEG spikes and associated interneuronal population bursts in thehippocampal hilar region of the rat. J Neurophysiol 73:1691-1705.

Campeau S, Watson S J, Jr. (2000) Connections of someauditory-responsive posterior thalamic nuclei putatively involved inactivation of the hypothalamo-pituitary-adrenocortical axis in responseto audiogenic stress in rats: an anterograde and retrograde tracttracing study combined with Fos expression. J Comp Neurol 423:474-491.

Cao J, Shen Y, Zhu L, Xu Y, Zhou Y, Wu Z, Li Y, Yan X, Zhu X (2012)miR-129-3p controls cilia assembly by regulating CP110 and actindynamics. Nature cell biology 14:697-706.

Clelland C D, Choi M, Romberg C, Clemenson G D, Jr., Fragniere A, TyersP, Jessberger S, Saksida L M, Barker R A, Gage F H, Bussey T J (2009) Afunctional role for adult hippocampal neurogenesis in spatial patternseparation. Science 325:210-213.

Couillard-Despres S, Winner B, Schaubeck S, Aigner R, Vroemen M, WeidnerN, Bogdahn U, Winkler J, Kuhn H G, Aigner L (2005) Doublecortinexpression levels in adult brain reflect neurogenesis. Eur J Neurosci21:1-14.

Creer D J, Romberg C, Saksida L M, van Praag H, Bussey T J (2010)Running enhances spatial pattern separation in mice. Proc Natl Acad SciUSA 107:2367-2372.

Crestani F, Lorez M, Baer K, Essrich C, Benke D, Laurent J P, Belzung C,Fritschy J M, Luscher B, Mohler H (1999) Decreased GABAA-receptorclustering results in enhanced anxiety and a bias for threat cues. NatNeurosci 2:833-839.

Decker M W (1987) The effects of aging on hippocampal and corticalprojections of the forebrain cholinergic system. Brain Res 434:423-438.

Deng W, Mayford M, Gage F H (2013) Selection of distinct populations ofdentate granule cells in response to inputs as a mechanism for patternseparation in mice. eLife 2:e00312.

Enkel T, Gholizadeh D, von Bohlen Und Halbach O, Sanchis-Segura C,Hurlemann R, Spanagel R, Gass P, Vollmayr B (2010) Ambiguous-cueinterpretation is biased under stress- and depression-like states inrats. Neuropsychopharmacology 35:1008-1015.

Ferrante M, Migliore M, Ascoli G A (2009) Feed-forward inhibition as abuffer of the neuronal input-output relation. Proc Natl Acad Sci USA106:18004-18009.

Frankland P W, Cestari V, Filipkowski R K, McDonald R J, Silva A J(1998) The dorsal hippocampus is essential for context discriminationbut not for contextual conditioning. Behav Neurosci 112:863-874.

Ge S, Yang C H, Hsu K S, Ming G L, Song H (2007) A critical period forenhanced synaptic plasticity in newly generated neurons of the adultbrain. Neuron 54:559-566.

Geinisman Y, deToledo-Morrell L, Morrell F, Persina I S, Rossi M (1992)Age-related loss of axospinous synapses formed by two afferent systemsin the rat dentate gyms as revealed by the unbiased stereologicaldissector technique. Hippocampus 2:437-444.

Gilbert P E, Kesner R P, Lee I (2001) Dissociating hippocampalsubregions: double dissociation between dentate gyms and CA1.Hippocampus 11:626-636.

Grillon C, Pine D S, Lissek S, Rabin S, Bonne O, Vythilingam M (2009)Increased anxiety during anticipation of unpredictable aversive stimuliin posttraumatic stress disorder but not in generalized anxietydisorder. Biol Psychiatry 66:47-53.

Gu Y, Arruda-Carvalho M, Wang J, Janoschka S R, Josselyn S A, FranklandP W, Ge S (2012) Optical controlling reveals time-dependent roles foradult-born dentate granule cells. Nat Neurosci 15:1700-1706.

Guzowski J F, McNaughton B L, Barnes C A, Worley P F (1999)Environment-specific expression of the immediate-early gene Arc inhippocampal neuronal ensembles. Nat Neurosci 2:1120-1124.

Hasselmo M E, Schnell E, Barkai E (1995) Dynamics of learning and recallat excitatory recurrent synapses and cholinergic modulation in rathippocampal region CA3. J Neurosci 15:5249-5262.

Hof P R, Morrison J H (2004) The aging brain: morphomolecular senescenceof cortical circuits. Trends Neurosci 27:607-613.

Ikrar T, Guo N, He K, Besnard A, Levinson S, Hill A, Lee H-K, Hen R, XuX, Sahay A (2013) Adult neurogenesis modifies excitability of thedentate gyms. Front Neural Circuits 7: 204.

Jovanovic T, Ressler K J (2010) How the neurocircuitry and genetics offear inhibition may inform our understanding of PTSD. Am J Psychiatry167:648-662.

Kheirbek M A, Klemenhagen K C, Sahay A, Hen R (2012) Neurogenesis andgeneralization: a new approach to stratify and treat anxiety disorders.Nature Neuroscience 15.

Kim J, Lee J E, Heynen-Genel S, Suyama E, Ono K, Lee K, Ideker T,Aza-Blanc P, Gleeson J G (2010) Functional genomic screen for modulatorsof ciliogenesis and cilium length. Nature 464:1048-1051.

Knoth R, Singec I, Ditter M, Pantazis G, Capetian P, Meyer R P, HorvatV, Volk B, Kempermann G (2010) Murine features of neurogenesis in thehuman hippocampus across the lifespan from 0 to 100 years. PLoS ONE5:e8809.

Krause M, Yang Z, Rao G, Houston F P, Barnes C A (2008) Altereddendritic integration in hippocampal granule cells of spatiallearning-impaired aged rats. J Neurophysiol 99:2769-2778.

Kubik S, Miyashita T, Guzowski J F (2007) Using immediate-early genes tomap hippocampal subregional functions. Learning & memory (Cold SpringHarbor, N.Y. 14:758-770.

Kuhn H G, Dickinson-Anson H, Gage F H (1996) Neurogenesis in the dentategyms of the adult rat: age-related decrease of neuronal progenitorproliferation. J Neurosci 16:2027-2033.

Leutgeb J K, Leutgeb S, Moser M B, Moser E I (2007) Pattern separationin the dentate gyms and CA3 of the hippocampus. Science 315:961-966.

Lin D, Boyle M P, Dollar P, Lee H, Lein E S, Perona P, Anderson D J(2011) Functional identification of an aggression locus in the mousehypothalamus. Nature 470:221-226.

Lissek S, Rabin S, Heller R E, Lukenbaugh D, Geraci M, Pine D S, GrillonC (2010) Overgeneralization of conditioned fear as a pathogenic markerof panic disorder. Am J Psychiatry 167:47-55.

Marr D (1971) Simple memory: a theory for archicortex. Philosophicaltransactions of the Royal Society of London 262:23-81.

Massa F, Koelh M, Wiesner T, Grosjean N, Revest J M, Piazza P V, AbrousD N, Oliet S H (2011) Conditional reduction of adult neurogenesisimpairs bidirectional hippocampal synaptic plasticity. Proc Natl AcadSci USA 108:6644-6649.

Matsuda M, Yamashita J K, Tsukita S, Furuse M (2010) abLIM3 is a novelcomponent of adherens junctions with actin-binding activity. Europeanjournal of cell biology 89:807-816.

McBain C J (2008) Differential mechanisms of transmission and plasticityat mossy fiber synapses. Prog Brain Res 169:225-240.

McClelland J L, Goddard N H (1996) Considerations arising from acomplementary learning systems perspective on hippocampus and neocortex.Hippocampus 6:654-665.

McHugh T J, Jones M W, Quinn J J, Balthasar N, Coppari R, Elmquist J K,Lowell B B, Fanselow M S, Wilson M A, Tonegawa S (2007) Dentate GymsNMDA Receptors Mediate Rapid Pattern Separation in the HippocampalNetwork. Science 317:94-99.

McNaughton B, Morris R (1987) Hippocampal synaptic enhancement andinformation storage within a distributed memory system. Trends Neurosci10:408-415.

Monosov I E, Hikosaka O (2013) Selective and graded coding of rewarduncertainty by neurons in the primate anterodorsal septal region. NatNeurosci 16:756-762.

Mori M, Gahwiler B H, Gerber U (2007) Recruitment of an inhibitoryhippocampal network after bursting in a single granule cell. Proc NatlAcad Sci USA 104:7640-7645.

Motley S E, Kirwan C B (2012) A parametric investigation of patternseparation processes in the medial temporal lobe. J Neurosci32:13076-13085.

Nakashiba T, Cushman J D, Pelkey K A, Renaudineau S, Buhl D L, McHugh TJ, Rodriguez Barrera V, Chittajallu R, Iwamoto K S, McBain C J, FanselowM S, Tonegawa S (2012) Young dentate granule cells mediate patternseparation, whereas old granule cells facilitate pattern completion.Cell 149:188-201.

Nakazawa K, Quirk M C, Chitwood R A, Watanabe M, Yeckel M F, Sun L D,Kato A, Carr C A, Johnston D, Wilson M A, Tonegawa S (2002) Requirementfor hippocampal CA3 NMDA receptors in associative memory recall. Science297:211-218.

Niibori Y, Yu T S, Epp J R, Akers K G, Josselyn S A, Frankland P W(2012) Suppression of adult neurogenesis impairs population coding ofsimilar contexts in hippocampal CA3 region. Nature communications3:1253.

Opendak M, Gould E (2011) New neurons maintain efficient stressrecovery. Cell Stem Cell 9:287-288.

O'Reilly R C, McClelland J L (1994) Hippocampal conjunctive encoding,storage, and recall: avoiding a trade-off. Hippocampus 4:661-682.

Pan W X, McNaughton N (2004) The supramammillary area: its organization,functions and relationship to the hippocampus. Prog Neurobiol74:127-166.

Peri T, Ben-Shakhar G, Orr S P, Shalev A Y (2000) Psychophysiologicassessment of aversive conditioning in posttraumatic stress disorder.Biol Psychiatry 47:512-519.

Piatti V C, Ewell L A, Leutgeb J K (2013) Neurogenesis in the dentategyms: carrying the message or dictating the tone. Front Neurosci 7:50.

Risold P Y, Swanson L W (1996) Structural evidence for functionaldomains in the rat hippocampus. Science 272:1484-1486.

Risold P Y, Swanson L W (1997) Connections of the rat lateral septalcomplex. Brain Res Brain Res Rev 24:115-195.

Rolls E T (1996) A theory of hippocampal function in memory. Hippocampus6:601-620.

Rolls E T, Kesner R P (2006) A computational theory of hippocampalfunction, and empirical tests of the theory. Prog Neurobiol 79:1-48.

Ruediger S, Spirig D, Donato F, Caroni P (2012) Goal-oriented searchingmediated by ventral hippocampus early in trial-and-error learning. NatNeurosci.

Ruediger S, Vittori C, Bednarek E, Genoud C, Strata P, Sacchetti B,Caroni P (2011) Learning-related feedforward inhibitory connectivitygrowth required for memory precision. Nature 473:514-518.

Sahay A, Scobie K N, Hill A S, O'Carroll C M, Kheirbek M A, Burghardt NS, Fenton A A, Dranovsky A, Hen R (2011) Increasing adult hippocampalneurogenesis is sufficient to improve pattern separation. Nature472:466-470.

Sahay A, Wilson D A, Hen R (2011a) Pattern separation: a common functionfor new neurons in hippocampus and olfactory bulb. Neuron 70:582-588.

Satvat E, Schmidt B, Argraves M, Marrone D F, Markus E J (2011) Changesin task demands alter the pattern of zif268 expression in the dentategyms. J Neurosci 31:7163-7167.

Sauerhofer E, Pamplona F A, Bedenk B, Moll G H, Dawirs R R, von HorstenS, Wotjak C T, Golub Y (2012) Generalization of contextual fear dependson associative rather than non-associative memory components. BehavBrain Res 233:483-493.

Saxe M D, Battaglia F, Wang J W, Malleret G, David D J, Monckton J E,Garcia A D, Sofroniew M V, Kandel E R, Santarelli L, Hen R, Drew M R(2006) Ablation of hippocampal neurogenesis impairs contextual fearconditioning and synaptic plasticity in the dentate gyrus. Proc NatlAcad Sci USA 103:17501-17506.

Schmidt B, Marrone D F, Markus E J (2012) Disambiguating the similar:the dentate gyms and pattern separation. Behav Brain Res 226:56-65.

Schmidt-Hieber C, Jonas P, Bischofberger J (2004) Enhanced synapticplasticity in newly generated granule cells of the adult hippocampus.Nature 429:184-187.

Scobie K N, Hall B J, Wilke S A, Klemenhagen K C, Fujii-Kuriyama Y,Ghosh A, Hen R, Sahay A (2009) Kruppel-like factor 9 is necessary forlate-phase neuronal maturation in the developing dentate gyms and duringadult hippocampal neurogenesis. J Neurosci 29:9875-9887.

Small S A, Chawla M K, Buonocore M, Rapp P R, Barnes C A (2004) Imagingcorrelates of brain function in monkeys and rats isolates a hippocampalsubregion differentially vulnerable to aging. Proc Natl Acad Sci USA101:7181-7186.

Small S A, Schobel S A, Buxton R B, Witter M P, Barnes C A (2011) Apathophysiological framework of hippocampal dysfunction in ageing anddisease. Nat Rev Neurosci 12:585-601.

Smith M L, Deadwyler S A, Booze R M (1993) 3-D reconstruction of thecholinergic basal forebrain system in young and aged rats. NeurobiolAging 14:389-392.

Smith T D, Adams M M, Gallagher M, Morrison J H, Rapp P R (2000)Circuit-specific alterations in hippocampal synaptophysinimmunoreactivity predict spatial learning impairment in aged rats. JNeurosci 20:6587-6593.

Snyder J S, Kee N, Wojtowicz J M (2001) Effects of adult neurogenesis onsynaptic plasticity in the rat dentate gyms. J Neurophysiol85:2423-2431.

Spalding K L, Bergmann O, Alkass K, Bernard S, Salehpour M, Huttner H B,Bostrom E, Westerlund I, Vial C, Buchholz B A, Possnert G, Mash D C,Druid H, Frisen J (2013) Dynamics of hippocampal neurogenesis in adulthumans. Cell 153:1219-1227.

Stanley D P, Shetty A K (2004) Aging in the rat hippocampus isassociated with widespread reductions in the number of glutamatedecarboxylase-67 positive interneurons but not interneuron degeneration.J Neurochem 89:204-216.

Stark S M, Yassa M A, Lacy J W, Stark C E (2013) A task to assessbehavioral pattern separation (BPS) in humans: Data from healthy agingand mild cognitive impairment. Neuropsychologia.

Thomas E, Dewolfe M, Sancar F, Todi N, Yadin E (2012)Electrophysiological analysis of the interaction between the lateralseptum and the central nucleus of the amygdala. Neurosci Lett 524:79-83.

Toner C K, Pirogovsky E, Kirwan C B, Gilbert P E (2009) Visual objectpattern separation deficits in nondemented older adults. Learning &memory (Cold Spring Harbor, N.Y. 16:338-342.

Torborg C L, Nakashiba T, Tonegawa S, McBain C J (2010) Control of CA3output by feedforward inhibition despite developmental changes in theexcitation-inhibition balance. J Neurosci 30:15628-15637.

Treves A, Rolls E T (1992) Computational constraints suggest the needfor two distinct input systems to the hippocampal CA3 network.Hippocampus 2:189-199.

Treves A, Tashiro A, Witter M E, Moser E I (2008) What is the mammaliandentate gyms good for? Neuroscience 154:1155-1172.

Tronel S, Belnoue L, Grosjean N, Revest J M, Piazza P V, Koehl M, AbrousD N (2010) Adult-born neurons are necessary for extended contextualdiscrimination. Hippocampus.

Tsetsenis T, Ma X H, Lo Iacono L, Beck S G, Gross C (2007) Suppressionof conditioning to ambiguous cues by pharmacogenetic inhibition of thedentate gyms. Nat Neurosci 10:896-902.

Vanni-Mercier G, Mauguiere F, Isnard J, Dreher J C (2009) Thehippocampus codes the uncertainty of cue-outcome associations: anintracranial electrophysiological study in humans. J Neurosci29:5287-5294.

Vazdarjanova A, Guzowski J F (2004) Differences in hippocampal neuronalpopulation responses to modifications of an environmental context:evidence for distinct, yet complementary, functions of CA3 and CA1ensembles. J Neurosci 24:6489-6496.

Villeda S A et al. (2011) The ageing systemic milieu negativelyregulates neurogenesis and cognitive function. Nature 477:90-94.

von Bohlen and Halbach O, Zacher C, Gass P, Unsicker K (2006)Age-related alterations in hippocampal spines and deficiencies inspatial memory in mice. Journal of neuroscience research 83:525-531.

Wang S H, Teixeira C M, Wheeler A L, Frankland P W (2009) The precisionof remote context memories does not require the hippocampus. NatNeurosci 12:253-255.

Wang Y, Arvanites A C, Davidow L, Blanchard J, Lam K, Yoo J W, Coy S,Rubin L L, McMahon A P (2012) Selective identification of hedgehogpathway antagonists by direct analysis of smoothened ciliarytranslocation. ACS chemical biology 7:1040-1048.

Wilson I A, Ikonen S, Gallagher M, Eichenbaum H, Tanila H (2005)Age-associated alterations of hippocampal place cells are subregionspecific. J Neurosci 25:6877-6886.

Wiltgen B J, Silva A J (2007) Memory for context becomes less specificwith time. Learning & memory (Cold Spring Harbor, N.Y. 14:313-317.

Xu W, Sudhof T C (2013) A neural circuit for memory specificity andgeneralization. Science 339:1290-1295.

Yang Z, Krause M, Rao G, McNaughton B L, Barnes C A (2008) Synapticcommitment: developmentally regulated reciprocal changes in hippocampalgranule cell NMDA and AMPA receptors over the lifespan. J Neurophysiol99:2760-2768.

Yassa M A, Lacy J W, Stark S M, Albert M S, Gallagher M, Stark C E(2011b) Pattern separation deficits associated with increasedhippocampal CA3 and dentate gyms activity in nondemented older adults.Hippocampus 21:968-979.

Yassa M A, Mattfeld A T, Stark S M, Stark C E (2011a) Age-related memorydeficits linked to circuit-specific disruptions in the hippocampus. ProcNatl Acad Sci USA 108:8873-8878.

Yassa M A, Muftuler L T, Stark C E (2010) Ultrahigh-resolutionmicrostructural diffusion tensor imaging reveals perforant pathdegradation in aged humans in vivo. Proc Natl Acad Sci USA107:12687-12691.

Yassa M A, Stark C E (2011) Pattern separation in the hippocampus.Trends Neurosci 34:515-525.

Yehuda R, LeDoux J (2007) Response variation following trauma: atranslational neuroscience approach to understanding PTSD. Neuron56:19-32.

Zhang J H, Chung T D, Oldenburg K R (1999) A Simple StatisticalParameter for Use in Evaluation and Validation of High ThroughputScreening Assays. Journal of biomolecular screening 4:67-73.

Zhou Z, Hong E J, Cohen S, Zhao W N, Ho H Y, Schmidt L, Chen W G, Lin Y,Savner E, Griffith E C, Hu L, Steen J A, Weitz C J, Greenberg M E (2006)Brain-specific phosphorylation of MeCP2 regulates activity-dependentBdnf transcription, dendritic growth, and spine maturation. Neuron52:255-269.

Other Embodiments

It is to be understood that while the invention has been described inconjunction with the detailed description thereof, the foregoingdescription is intended to illustrate and not limit the scope of theinvention, which is defined by the scope of the appended claims. Otheraspects, advantages, and modifications are within the scope of thefollowing claims.

What is claimed is:
 1. A method of identifying a candidate smallmolecule inhibitor of Ablim3, the method comprising: providing a testsample comprising a population of cells that express Ablim3; contactingthe sample with a test compound; detecting subcellular localization ofAblim3 protein in the cells in the presence of the test compound;determining whether the Ablim3 protein is localized to adherensjunctions in the cells in the presence of the cells; selecting as acandidate inhibitor a test compound that reduces localization of Ablim3protein to adherens junctions.
 2. The method of claim 1, wherein thecells express an Ablim3 reporter construct, wherein Ablim3 is linked toa detectable label, preferably a fluorescent protein.
 3. The method ofclaim 1, further comprising evaluating actin cytoskeleton in the cells,and selecting as a candidate inhibitor a test compound that reduceslocalization of Ablim3 protein to adherens junctions and does notdisrupt the actin cytoskeleton.
 4. The method of claim 1, furthercomprising: administering a candidate compound to an animal model;evaluating an effect of the candidate compound on memory in the animalmodel; and selecting a compound that improves memory in the animalmodel.
 5. The method of claim 1, wherein the compound improves patternseparation in the animal model.
 6. The method of claim 1, wherein thetest compound is a polypeptide, polynucleotide, inorganic large or smallmolecule, or organic large or small molecule.